For the longest time, the previous edit summary was retained when editing the post again within the 5 minute grace period. It appears that now, that is no longer true, and it's extremely annoying.
Every time you edit within the grace period, it appends a new message to the edit summary unless you type something in. I really don't feel like finding my message again or re-typing it. Yet if I continue editing adding a few characters at a time, the edit message will end up looking like this:
Eventually, if you do it too many times, the system won't even let you save edits anymore without changing the edit reason. Most likely the message is now too long. Proper error message, please?
If the system is forced to automatically append a new message, it should check the previous ones. I've reported a similar bug report about "edited tags" previously.
When was this change even made? If this change was intentional, I strongly encourage you to reconsider. Usually when I edit within the grace period, it's to fix small spelling or punctuation errors that I hadn't noticed when I first submitted. The edit reason I entered is still the only edit reason. If I feel I need to add to it, or I want to change it, then I will. Don't make me re-type things just to keep the edit reason from appending useless text.