My workaround is to go into an editable field and turn it off.
It's always "ABC" on my 7100 (never had "123"), so I'll just pop into messages, click REPLY, press/hold the * key until "ABC" goes away, and then cancel my reply.
I have no idea what causes it to happen. It doesn't happen often for me, but it always seems to turn itself on when I'm nowhere near an 'editable' field. ??