After you file

I have a .taxfile and .pdf dated 4/15 but when I open the .taxfile it shows the changed amount and when I exit, it saves and overwrites my .taxfile and the date on the timestamp becomes 5/25. Before if anything changed I would be prompted to save or not. But today even though I didn't make any changes it autosaves and overwrites what was in my 4/15 .taxfile.