I wonder if "keybounce" is the right term for this symptom. I don't think it is anymore. Maybe it's just the break of the shift key is slower than I'm used to. I do this on other keyboards, too.
Oh, and obligatory transposition test:
qwer
qwer
qwer
uiop
uiop
uiop
But when I type "if" or "it" it often ends up "fi" and "ti." GO figure.