Every once in a while I see some strange behavior from my 7Ds, too. For example, on a couple isolated occasions I've seen the focus mode change unexpectedly. I can't see how I would accidentally bump the M.Fn button to do that myself, but haven't entirely ruled that out as a possibility... (I've long had issues with the mode dial on various cameras' lefthand shoulder... accidentally bumping and changing those. Thank heaven Canon is finally incorporating a locking button on that dial, with the 60D and can be retrofitted to 7D and 5DII.)
I think all cameras these days are prone to "computer glitches", might need a forced reboot to clear memory instructions that get garbled or corrupted, same as a computer occasionally needs. That's just the price we pay for a highly computerized camera! Just like computers, models come and go so quickly they never get fully ironed out before release (thus all the firmware updates) and some of the more minor glitches never do get fully addressed before we're "upgrading" to the latest and greatest model.
Removing all the batteries (inlc. the little silver memory battery), as described above, forces a reboot and clears memory. It's easy enough to try, too... just leave them out for half an hour to an hour... or a faster way is to turn the camera on without any batteries in it, press the shutter release button once... it won't fire but this drains any remaining power from the camera. This works with some models, not with others, but doesn't hurt to try. Reinstall the batteries, turn the camera on and check the date/time. You should need to reset it. If not, repeat the battery removal procedure. Note that at least one recent model - 60D - you can't do this procedure because there's no easy access to the little silver memory battery.
Speaking of compter similarities... For the first year I was using them, I almost feel like a beta tester shooting with 7D's AF system!
OP, as to your grip issues... Have you tried cleaning all the contacts between the grip and the camera? I'd suggest putting a few drops of isopropyl (rubbing) alcohol on a clean, lint free cloth, then wipe all the contacts with that. You might need to put the cloth over a "tool" to reach the contacts up inside the camera (maybe try a wooden coffee stir stick from Starbucks or similar?). Though I think it's unrelated, while doing some cleaning it might be a good idea to clean the lens-to-camera contacts the same way, both inside the front of the camera and on the back of each of your lenses (be careful not to touch the camera's mirror, lens' optics, etc.) Sometimes finger oils or even manufacturing/lubricating oils even manufacturing residues (new lens) can get on contacts and interrupt the low-voltages trying to cross them. Besides, it cheap and easy to try cleaning them.
Also operate the grip's off/on switch a few times. Those kinds of switches are usually self-cleaning, but only when they are operated occasionally. They can get corrosion in them when not operated often or at all (I leave mine set "on" pretty much from new).