In reply to - "When was the version in which this bug was fixed become available? Is it possible that the document was deleted before the update and I have only just realized it now? I am pretty sure I accessed and edited this file late last week, but had not needed to look at it for a few days. Is there any way I could check to see if my error occurred before the update?"
1. Go to "Acrobat.com" tab in your Adobe Reader app
2. Look for the corrupted document in the Acrobat.com listing
3. What is the date mentioned just below the entry that shows the corrupted document. This is the modified date. This date would help us identify when this issue occurred.