Mysterious Rearranging Content

I more or less inherited a Drupal site from a previous web firm. There is one section that in the year and a half of working with the site I have never had to touch. Recently they have started having issues with the content switching itself out for other content. For instance, the slideshow (an entity reference) on module a changes to be that from module b. I updated field_entities and that seemed to fix it but then two days later the links in an embedded field collection started changing. Some of them were just switched with another module, some of them had the another modules link appended onto the beginning or the end of the correct link, and one had another modules link inserted into the middle of the link. I have never seen anything like this on any site I have worked for. Any ideas on what can be going on? I don’t even know where to start to trouble shoot this.

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