In 5+ years of doing RTI I've never had a remote "lock up" because of a code or button press.

I have had my T3v lock up a couple times over the course of 2+ years... I chalked it up to a random glitch... and the fact that I have custom pictures set as backgrounds which slows things down a touch.

I have had plenty of T2C remotes lock up because of the infamous white screen of death. The symptoms there start out happening every once in a while then start happening more frequently until final death.

Your situation sounds like random glitches, but should be monitored.