I cannot send PM's to d/\t/\m/\gg0+ , it says "cannot find recipient" and then displays his name as d/t/m/gg0+ to this tells me it has something to do with the slashes in his name. If i add the slashes back in the issue happens anyways.
Oh, and I don't like to name names, but he is the only one i'm having a problem sending to. d/\t/\: if you want i'll remove your name from my post.
This is interesting, and probably a side effect of the sanitizer escaping his "unescapes". That format is used in SQL to escape slashes.
Were you able to send that user messages before the update?