same to me: try to return the old title, diffname, artist and recopy and paste the beatmapid (after upload and have this problem) in to the new code!
After that, return to the edit menu and see the text "Update to lastest version" appears or not (if it's Not Submitted, make sure about the beatmap id, it's still -1 or it's your current id now?) and return to that map and upload it, after that, try to change diff name or title and artist like the way you want! and when you can't do like that and still can't update it and you have already upload the same map with the same mp3, call QAT to delete the unnesssary map!
I was think this is a bug too!