多摩勉強会/遠藤

ページの編集中「保存」でブロック内が空になる

5.7.5.9を使用しているのですが、
新規にページ作成した場合も、既存のページを編集している場合にも、ブロックを配置して、
該当ブロックの編集が終わって、「保存」ボタンを押下すると、
ブロックの中身が空に成ってしまう場合があります。

事象が起こる場合は、
既存のHTMLブロックを編集して、「保存」を押下しても、
編集が保存されないだけでなく、もともと保存されていたHTML毎無くなってしまいます。

また、まれに、同じページ内の編集対象ではないブロックが空になる事もあります。

サーバ側のアクセスログを見ても、原因となりそうなログが見つけられず、対策方法が見つけられておりません。

過去の投稿で似たような事象があったのですが、
http://concrete5-japan.org/community/forums/bug/post-10021/
状況が違うようです。

確認すべきポイントなどあれば、教えて頂けないでしょうか？

システム情報は以下の通りです。

# concrete5 Version
Core Version - 5.7.5.9
Version Installed - 5.7.5.9
Database Version - 20160615000000

# concrete5 Packages
Block Designer (2.5.3), Block Designer Pro (2.5.0), Event Calendar (3.3.6), List Designer (2.0.0), Newsprint (1.0.2), Open Graph Tags Lite (2.1.3), Page List+ (1.3.4), Simple Slider (1.0), Social Share Lite (2.1.3).

# concrete5 Overrides
blocks/page_title/templates/archive.php, blocks/page_title/templates/byline.php, blocks/page_title/templates, blocks/page_title, blocks/image/templates/withco/view.php, blocks/image/templates/withco/view.css, blocks/image/templates/withco, blocks/image/templates, blocks/image, blocks/external_form/form/controller/apply_form.php, blocks/external_form/form/controller, blocks/external_form/form/apply_form.php, blocks/external_form/form, blocks/external_form, blocks/holiday_hospital/composer.php, blocks/holiday_hospital/config.json, blocks/holiday_hospital/view.php, blocks/holiday_hospital/db.xml, blocks/holiday_hospital/controller.php, blocks/holiday_hospital/js_form/bootstrap.min.js, blocks/holiday_hospital/js_form/moment.js, blocks/holiday_hospital/js_form/bootstrap-datetimepicker.min.js, blocks/holiday_hospital/js_form, blocks/holiday_hospital/icon.png, blocks/holiday_hospital/edit.php, blocks/holiday_hospital/add.php, blocks/holiday_hospital/fonts/glyphicons-halflings-regular.svg, blocks/holiday_hospital/fonts/glyphicons-halflings-regular.woff, blocks/holiday_hospital/fonts/glyphicons-halflings-regular.ttf, blocks/holiday_hospital/fonts/glyphicons-halflings-regular.eot, blocks/holiday_hospital/fonts, blocks/holiday_hospital/css_form/bootstrap.fonts.css, blocks/holiday_hospital/css_form/bootstrap-datetimepicker.min.css, blocks/holiday_hospital/css_form, blocks/holiday_hospital/form.php, blocks/holiday_hospital, blocks/page_list_plus/templates/withco/view.php, blocks/page_list_plus/templates/withco/view.css, blocks/page_list_plus/templates/withco, blocks/page_list_plus/templates/top_list/view.php, blocks/page_list_plus/templates/top_list/view.css, blocks/page_list_plus/templates/top_list, blocks/page_list_plus/templates, blocks/page_list_plus, blocks/form/controller.php, blocks/form, blocks/google_map/controller.php, blocks/google_map, blocks/page_attribute_display/templates/WithcoCategory/view.php, blocks/page_attribute_display/templates/WithcoCategory/view.css, blocks/page_attribute_display/templates/WithcoCategory, blocks/page_attribute_display/templates, blocks/page_attribute_display, controllers/single_page/dashboard/reports/forms.php, controllers/single_page/dashboard/reports/ownforms.php, controllers/single_page/dashboard/reports, controllers/single_page/dashboard, controllers/single_page, languages/ja_JP/LC_MESSAGES/messages.mo, languages/ja_JP/LC_MESSAGES, languages/ja_JP, languages/it_IT/LC_MESSAGES/messages.mo, languages/it_IT/LC_MESSAGES, languages/it_IT, languages/el_GR/LC_MESSAGES/messages.mo, languages/el_GR/LC_MESSAGES, languages/el_GR, languages/sv_SE/LC_MESSAGES/messages.mo, languages/sv_SE/LC_MESSAGES, languages/sv_SE, languages/fr_FR/LC_MESSAGES/messages.mo, languages/fr_FR/LC_MESSAGES, languages/fr_FR, languages/ru_RU/LC_MESSAGES/messages.mo, languages/ru_RU/LC_MESSAGES, languages/ru_RU, languages/tr_TR/LC_MESSAGES/messages.mo, languages/tr_TR/LC_MESSAGES, languages/tr_TR, languages/cs_CZ/LC_MESSAGES/messages.mo, languages/cs_CZ/LC_MESSAGES, languages/cs_CZ, languages/fi_FI/LC_MESSAGES/messages.mo, languages/fi_FI/LC_MESSAGES, languages/fi_FI, languages/da_DK/LC_MESSAGES/messages.mo, languages/da_DK/LC_MESSAGES, languages/da_DK, languages/es_PY/LC_MESSAGES/messages.mo, languages/es_PY/LC_MESSAGES, languages/es_PY, languages/de_DE/LC_MESSAGES/messages.mo, languages/de_DE/LC_MESSAGES, languages/de_DE, languages/pt_BR/LC_MESSAGES/messages.mo, languages/pt_BR/LC_MESSAGES, languages/pt_BR, mail/block_form_submission_user.php, mail/mail_complete.php, single_pages/dashboard/reports/ownforms.php, single_pages/dashboard/reports, single_pages/dashboard, themes/withco/page_theme.php, themes/withco/blank.php, themes/withco/css/html5reset-1.6.1.css, themes/withco/css/style.css, themes/withco/css, themes/withco/elements/header.php, themes/withco/elements/footer.php, themes/withco/elements, themes/withco/description.txt, themes/withco/withcoblog.php, themes/withco/default.php, themes/withco/thumbnail.png, themes/withco/js/smartrollover.js, themes/withco/js/jquery.bxslider.min.js, themes/withco/js/jquery-1.8.2.min.js, themes/withco/js, themes/withco/images/nav01_on.png, themes/withco/images/mainvisual_02.jpg, themes/withco/images/f_mail.png, themes/withco/images/f_img02.png, themes/withco/images/more_arr.png, themes/withco/images/sample02.JPG, themes/withco/images/h2.png, themes/withco/images/feature03.png, themes/withco/images/nav04_on.png, themes/withco/images/nav03_off.png, themes/withco/images/nav02_on.png, themes/withco/images/sample.png, themes/withco/images/nav04_off.png, themes/withco/images/logo.png, themes/withco/images/f_tel.png, themes/withco/images/nav05_on.png, themes/withco/images/feature02.png, themes/withco/images/f_img01.png, themes/withco/images/feature01.png, themes/withco/images/contents_bg.png, themes/withco/images/nav03_on.png, themes/withco/images/nav02_off.png, themes/withco/images/nav01_off.png, themes/withco/images/wood.jpg, themes/withco/images/nav05_off.png, themes/withco/images/wood.png, themes/withco/images/mainvisual_01.jpg, themes/withco/images, themes/withco/top.php, themes/withco, blocks/page_title/templates/archive.php, blocks/page_title/templates/byline.php, blocks/page_title/templates, blocks/page_title, blocks/image/templates/withco/view.php, blocks/image/templates/withco/view.css, blocks/image/templates/withco, blocks/image/templates, blocks/image, blocks/external_form/form/controller/apply_form.php, blocks/external_form/form/controller, blocks/external_form/form/apply_form.php, blocks/external_form/form, blocks/external_form, blocks/holiday_hospital/composer.php, blocks/holiday_hospital/config.json, blocks/holiday_hospital/view.php, blocks/holiday_hospital/db.xml, blocks/holiday_hospital/controller.php, blocks/holiday_hospital/js_form/bootstrap.min.js, blocks/holiday_hospital/js_form/moment.js, blocks/holiday_hospital/js_form/bootstrap-datetimepicker.min.js, blocks/holiday_hospital/js_form, blocks/holiday_hospital/icon.png, blocks/holiday_hospital/edit.php, blocks/holiday_hospital/add.php, blocks/holiday_hospital/fonts/glyphicons-halflings-regular.svg, blocks/holiday_hospital/fonts/glyphicons-halflings-regular.woff, blocks/holiday_hospital/fonts/glyphicons-halflings-regular.ttf, blocks/holiday_hospital/fonts/glyphicons-halflings-regular.eot, blocks/holiday_hospital/fonts, blocks/holiday_hospital/css_form/bootstrap.fonts.css, blocks/holiday_hospital/css_form/bootstrap-datetimepicker.min.css, blocks/holiday_hospital/css_form, blocks/holiday_hospital/form.php, blocks/holiday_hospital, blocks/page_list_plus/templates/withco/view.php, blocks/page_list_plus/templates/withco/view.css, blocks/page_list_plus/templates/withco, blocks/page_list_plus/templates/top_list/view.php, blocks/page_list_plus/templates/top_list/view.css, blocks/page_list_plus/templates/top_list, blocks/page_list_plus/templates, blocks/page_list_plus, blocks/form/controller.php, blocks/form, blocks/google_map/controller.php, blocks/google_map, blocks/page_attribute_display/templates/WithcoCategory/view.php, blocks/page_attribute_display/templates/WithcoCategory/view.css, blocks/page_attribute_display/templates/WithcoCategory, blocks/page_attribute_display/templates, blocks/page_attribute_display, controllers/single_page/dashboard/reports/forms.php, controllers/single_page/dashboard/reports/ownforms.php, controllers/single_page/dashboard/reports, controllers/single_page/dashboard, controllers/single_page, languages/ja_JP/LC_MESSAGES/messages.mo, languages/ja_JP/LC_MESSAGES, languages/ja_JP, languages/it_IT/LC_MESSAGES/messages.mo, languages/it_IT/LC_MESSAGES, languages/it_IT, languages/el_GR/LC_MESSAGES/messages.mo, languages/el_GR/LC_MESSAGES, languages/el_GR, languages/sv_SE/LC_MESSAGES/messages.mo, languages/sv_SE/LC_MESSAGES, languages/sv_SE, languages/fr_FR/LC_MESSAGES/messages.mo, languages/fr_FR/LC_MESSAGES, languages/fr_FR, languages/ru_RU/LC_MESSAGES/messages.mo, languages/ru_RU/LC_MESSAGES, languages/ru_RU, languages/tr_TR/LC_MESSAGES/messages.mo, languages/tr_TR/LC_MESSAGES, languages/tr_TR, languages/cs_CZ/LC_MESSAGES/messages.mo, languages/cs_CZ/LC_MESSAGES, languages/cs_CZ, languages/fi_FI/LC_MESSAGES/messages.mo, languages/fi_FI/LC_MESSAGES, languages/fi_FI, languages/da_DK/LC_MESSAGES/messages.mo, languages/da_DK/LC_MESSAGES, languages/da_DK, languages/es_PY/LC_MESSAGES/messages.mo, languages/es_PY/LC_MESSAGES, languages/es_PY, languages/de_DE/LC_MESSAGES/messages.mo, languages/de_DE/LC_MESSAGES, languages/de_DE, languages/pt_BR/LC_MESSAGES/messages.mo, languages/pt_BR/LC_MESSAGES, languages/pt_BR, mail/block_form_submission_user.php, mail/mail_complete.php, single_pages/dashboard/reports/ownforms.php, single_pages/dashboard/reports, single_pages/dashboard, themes/withco/page_theme.php, themes/withco/blank.php, themes/withco/css/html5reset-1.6.1.css, themes/withco/css/style.css, themes/withco/css, themes/withco/elements/header.php, themes/withco/elements/footer.php, themes/withco/elements, themes/withco/description.txt, themes/withco/withcoblog.php, themes/withco/default.php, themes/withco/thumbnail.png, themes/withco/js/smartrollover.js, themes/withco/js/jquery.bxslider.min.js, themes/withco/js/jquery-1.8.2.min.js, themes/withco/js, themes/withco/images/nav01_on.png, themes/withco/images/mainvisual_02.jpg, themes/withco/images/f_mail.png, themes/withco/images/f_img02.png, themes/withco/images/more_arr.png, themes/withco/images/sample02.JPG, themes/withco/images/h2.png, themes/withco/images/feature03.png, themes/withco/images/nav04_on.png, themes/withco/images/nav03_off.png, themes/withco/images/nav02_on.png, themes/withco/images/sample.png, themes/withco/images/nav04_off.png, themes/withco/images/logo.png, themes/withco/images/f_tel.png, themes/withco/images/nav05_on.png, themes/withco/images/feature02.png, themes/withco/images/f_img01.png, themes/withco/images/feature01.png, themes/withco/images/contents_bg.png, themes/withco/images/nav03_on.png, themes/withco/images/nav02_off.png, themes/withco/images/nav01_off.png, themes/withco/images/wood.jpg, themes/withco/images/nav05_off.png, themes/withco/images/wood.png, themes/withco/images/mainvisual_01.jpg, themes/withco/images, themes/withco/top.php, themes/withco

# concrete5 Cache Settings
Block Cache - On
Overrides Cache - On
Full Page Caching - On - If blocks on the particular page allow it.
Full Page Cache Lifetime - Every 6 hours (default setting).

# Server Software
nginx/1.8.1

# Server API
fpm-fcgi

# PHP Version
5.6.22

# PHP Extensions
apc, apcu, bz2, calendar, cgi-fcgi, Core, ctype, curl, date, dom, ereg, exif, fileinfo, filter, ftp, gd, gettext, hash, iconv, json, libxml, mbstring, mcrypt, mhash, mysql, mysqli, mysqlnd, openssl, pcre, PDO, pdo_mysql, pdo_sqlite, Phar, posix, Reflection, session, shmop, SimpleXML, soap, sockets, SPL, sqlite3, standard, sysvmsg, sysvsem, sysvshm, tidy, tokenizer, wddx, xdebug, xhprof, xml, xmlreader, xmlwriter, xsl, Zend OPcache, zip, zlib.

# PHP Settings
max_execution_time - 180
log_errors_max_len - 1024
max_file_uploads - 20
max_input_nesting_level - 64
max_input_time - 60
max_input_vars - 1000
memory_limit - 128M
post_max_size - 8M
sql.safe_mode - Off
upload_max_filesize - 5M
mysql.max_links - Unlimited
mysql.max_persistent - Unlimited
mysqli.max_links - Unlimited
mysqli.max_persistent - Unlimited
pcre.backtrack_limit - 1000000
pcre.recursion_limit - 100000
session.cache_limiter - no value
session.gc_maxlifetime - 1440
soap.wsdl_cache_limit - 5
xdebug.max_nesting_level - 256
xdebug.max_stack_frames - -1
xdebug.var_display_max_children - 128
xdebug.var_display_max_data - 512
xdebug.var_display_max_depth - 3
opcache.max_accelerated_files - 4000
opcache.max_file_size - 0
opcache.max_wasted_percentage - 5