I had this issue on 2 different jobs. The first one the client is out of town so haven't made it back there. The second client I just ended up taking the Comcast box back and swapping it out for a DCT box. I have gone through 3 different remotes and even came off of RF and went to an IR receiver. When I went to the IR receiver we got nothing at all. As soon as the RNG box came out and the DCT went in everything worked 100% with no glitches, flitches, bugs or headaches. Thankfully the client was understanding but it really doesn't make us look good. I found room light to effect those boxes as well as if there were alot of different components on.

Just my $.02