FYI, now two years in, this problem continues. Mine didn't appear until last month, and it's the same symptom as others experienced: channel change takes 20 seconds to function, commands are stored and executed en-masse. Makes the service unusable. Motorola QIP6416-2 HD/DVR
This is NOT the original problem, but a new one introduced by recent updates. The Original was mostly solved. I would say start a new thread, except there is a long thread just about problems the the new IMG.
On a different note you probably want to get your Arris (formerly Motorola) 6xxx receiver replaced. Look for threads about Mpeg-4 channels added and find a channel in your package. Then report you don't see that channel, and they should give you a free upgrade.
After years of frustration with my laggy Verizon DVRs (which I've replaced a few times to no avail), I'm moving on to Tivo. It's costing me $200 up front but $2 cheaper a month, and should end my ranting. Verizon should be ashamed of peddling such garbage.