User blog comment:Rappy 4187/Technical Update: April 30, 2013/@comment-5085186-20130512210156

I didn't see this thread so reported the "Forum threads cannot be renamed" via Special Contact. However, I also could not change the subject line on a message left on my wall; it seems to have the same issue as the forum threads (the rename shows and then reverts with reload).

I reported both but figured I'd mention it here in case it helps with research.