It’s probably not a pI3 thing, but who knows. It doesn’t do this for me. What version of OS X are you running? Do you have any other apps or utilities running that might be intercepting those commands?
When you hit cmd+R, do you see the “Action” menu at the top of the screen highlight? (because cmd+R is the “rewind” function in that menu). If not, something is intercepting the keystroke combo.