How do I change my community username? I don't see an option when editing my profile.
Why does my old username still appear on my posts?
At the moment, changing your screen name using your Adobe Account doesn't appear to be working. At least one bug report has been made in the both this forum and the Community Feedback forum. I suggest liking one or all of them to make the problem more visible to the support teams.
Log-in to your Adobe account profile page. I don't know if changes there will immediately show up in the forums, however. I reported a bug a few days ago. I don't know if it was fixed yet.
It hasn't. I changed my screen name yesterday and it hasn't propagated. At least one of the people who asked about this yesterday had changed their screen name two days before and it still hadn't updated.