When changing channels sometimes on the Comcast Motorola HD Cable box (usually from a PLII source to a DD 5.1 source or vice versa) you can hear a split second of the channel your changing to and then the channel comes on. I hope you understand what I am describing. I have my Cable box hooked up from optical out to my receiver. What causes this. Comcast just did some kind of an update two days ago and it wasn't doing this before the update but I remember the same thing around 8 or 9 months ago. What causes this and can it be eliminated? Any help is very appreciated.