I'm not entirely familiar with the software, but I will try and explain what we are seeing as best i can.
A user has created a form for other users to submit data with. This form includes a date field. When a user edits an already submitted form, the date always goes back one day. If it says 6/30 and you hit edit, it changes to 6/29. If you save that, and hit edit again, it changes to 6/28.
We are currently on version 3.0.3.