I have a vague recollection that this might have been raised in the past, but this isn't something that I've come across for a while so I thought that I'd ask.
For some reason, if I try to send a PM to kingk123
, I'm unable to locate their username in the search field. I can get around this and send successfully by using the "write PM" button from their profile page (or from the profile summary from clicking on their username in a thread), but I can't see any reason why their username won't show when doing this manually.
There don't seem to be any odd characters in their username that might be throwing it off, so... any ideas?