Data partially disappears from database

We periodically find that content on our site (shelburnefarms.org) has partially disappeared. The text on a page (entered into a rich text area) will disappear, but only partially. It's always cut off at the end, not in the middle. Otherwise, we can't derive a pattern. The number of characters are not consistent, nor is there a consistent character that ends the remaining content. This happens across content types and has occurred three times, over several months. We aren't able to find any related issues in the DB log. When we look at the database, the content is consistent with what displays on the site. Only a few people have access to content editing, so we're sure this isn't user error.

Relevant History: We originally developed this site on an A2 shared hosting server. We did not face this issue during development. We migrated the site to Acorn Hosting shared servers and, at the time, found that several pages dropped partial content during migration. We decided this must have been a flawed database export or import and we added the content back, assuming this would be fixed. Later, we found the multiple instances of content dropping, sometimes on the very same nodes we had fixed before, sometimes on different nodes. We asked Acorn to review their databases and they had no insight.

We have developed many D7 sites, hosting on Acorn, and we've never faced this issue. We can't figure out what might contribute to it. We can't re-create it.

The Acorn (current) server details are:
PHP 5.3.24
Database: 5.5.32-cll
Apache: 2.2.24

The A2 (previous) server details are:
PHP 5.3.18
Database: 5.1.63-cll
Apache: 2.2.24
(There is some chance that these details have changed since the site was originally migrated.)

Thanks for any insight you may have on where to look or what to try!