Multi-line fields lose data when saving/signing

I create online forms for a medical company and Acrobat DC works great for what I need to do, mostly convert paper forms to something we can fill out online. To this purpose we need to be able to both save and sign the documents.

Recently we have found that when a document is signed multiple times or saved multiple times and then signed any multi-line fields lose data. It looks as if the individual lines get pushed further and further apart every time its signed till lines are pushed out of the box and gone.

This is an example of what it should look like:

  This is what it looks like after multiple saves: 

Any help or advice would be appreciated.