HELP: Form field content disappears when users save/reopen

I build a ton of forms using InDesign and then Acrobat Pro to refine the fillable fields, but this is the only one that has random fields just "empty" when the user saves and re-opens. It happens when users complete the form, save and then send the PDF in a (secure) email between different providers who are all working on the document. 

Other than a clear form button at the top, I can't find any associated script that would cause fields to be cleared. Any ideas why this might happen and what I can do as the form builder to avoid it?

(I've attached both a clean version of the form and the extended version. I also linked below to a blank version of the form below. Unfortunately, examples I have that are filled out have  private/protected data, so I can't share them.)

Form that doesn't erases field content when people save/reopen