Thanks for the reply. What's baffling me is why the console was shutting down. Is that a normal consequence of a loss of signal between the console and a Pro controller, or of the controller losing power? I only got the "communications have been interrupted" message the first time it happened. On subsequent tests the console just turned straight off. Very, very bizarre. Like I said, up to that point never a problem.
I think I'll have to get the controller checked out (though it's working normally again now). Thanks for the help, guys. Nice forum.