Just got my 6D, fired it up and noticed the same "irregular communication" warning except mine says...Warning - You not spend your money with Canon, this battery not genuine. You Bad! NO BATTERY STATUS FOR YOU!
Oddly enough, even though none of the other menu items have sound, this one actually spoke the last part to me like the the Soup Nazi from Seinfeld but with a Japanese accent. Then it ended with the Pac-Man game over jingle. I actually thought it was pretty cool and plan to buy more non-genuine batteries so I hear it more often.
Seriously, this is an obvious attempt by Canon to 'root out' all the counterfit batteries that are becoming more and more of a problem. I understand the point on this because a lot of people get ripped off by very good looking fakes that cost the same price as a genuine battery. OTOH, when I intentionally buy an aftermarket battery for half the price (still not cheap) that works perfectly well and isn't trying to rip me off, I don't like Canon slapping me down for it and denying me functionality. That's just mean. (Just like Apple! Punish the end user because they can.)
In the end, we users are the losers either way so while I think Canon is fine alerting the user about the non-genuine battery, they definitely should not hide the gesture behind a confusing error msg instead of just saying it outright. And I think they are being pretty crappy/uncool by disabling the status information to punish you.
Come on Canon! You have 99% of my money already. Stop pissing me off over a simple accessory.
End of Rant.