On the 659 and 680, if a key is not assigned in Picture/Sound mode, then it sends the command from the "main" device for that activity. In your case, that would be your PVR. Check the Picture key mapping from the activity button customization (instead of from the TV device customization). Also make sure you map any key you plan to use for the Sound/Picture mode - don't leave it/them blank unless you want the one(s) from the "main" activity device. The "main" activity device is the 1st one listed on the left.