I'm concerned about some peculiar behavior that occasionally occurs shortly after changing channels or when a show cuts to/from a commercial. The set appears to loose synchronization for short periods resulting in loss of picture and sound and "block patterns". This usually clears up in a couple of seconds, but on rare occasions, I have to switch to another channel and come back to get a normal picture. I'm using a Comcast Motorola 6208 which also appears to delay broadcasts about 3.5 seconds relative to the Comcast SD simulcast shown on an old CRT TV. Is the problem with my new Panasonic 50PHD6UY, Cable Box, or Comcast?