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.
As this thread is now over two years old, it will be locked in order to keep discussions current. If you have the same or a similar question/issue we invite you to start a new thread on the topic.