hmm... I'm not for sure...
but i think i remember something like this... when you have typed enough letters, to the point where there are no other matches...
for instance "yan" your name will auto-fill the box, i believe... but if you press tab to continue, your name may still be there, but i don't think it will fully register.
pretty sure even though the name auto-filled into the box, you still have to click the icon with your name, clan/community flags.
not sure its a bug... its just the way the cookie crumbles..all though, if it is possible to fix that, it would be nice.