There was recently a question about how improving an edit caused the previous revision to appear when you clicked the edit button again (but I can't find it for some reason). I recently encountered this issue, when I improved an edit and removed the signature from the post. After submitting, I realized I should fix up the first line of the post as well, but didn't notice that the signature was present in the text again (as per the previous revision).
Now what's even worse is it recorded my two edits as separate edits, a mere 16 seconds apart. What happened to my 5 minute grace period!? How on Earth did the system even confuse these two events in order to not grant me the grace period? What happens with edits that it would think 5 minutes have passed? Did it not see me as the same user or something?
So now this revision history is labeled with two revision from me. The first one with two reasons, one changing the first line which resulted in an overall deletion of characters, and the second re-deleting the signature line at the bottom after noticing it had been re-added.
First edit timestamp:
Second edit timestamp: