Not sure what caused this. Been running everything fine for months. I did do the most recent update (to version 4.5.602.MB810.Verizon.en.US), but it worked fine for a few days.
I'm finding my keyboard freezing, in all applications (Handcent, Facebook, Twitter, Gmail), when I try to use any form of punctuation mark (period, comma, question mark, etc). It happens sporadically and seems to have no common denominator. If it happens while replying in Handcent (quick text mode or full app mode), I can still hit send - but then it ends up sending duplicates of the text message. Facebook it will post the comment only once it seems.
As it's across multiple apps, this seems more like a system issue. I've gone through and cleared my cache and data for the multi-touch keyboard. I've also downloaded a third party app to clear out all my cache as I, too, had the problem with the disappearing keyboard. But none of this seems to fix it.
Any suggestions? Is there a way to rollback to the previous Android version, even though it worked fine for a few days?