I recorded Saturday Night Live (SNL) from a local TV station last night. Upon playback I say Channels skip part of the show. Near the end of Weekend Update the cast said they would play some clips of Norm MacDonald as a tribute. Channels skipped over the clips. I know this because the episode is a repeat that watched a few weeks ago. I'm new to Channels and still evaluating it. I'm suspicious that Channels is skipping parts of programs and I don't know it.
In the timeline view you can see where commercials were detected versus where the show content was detected. The program used by Channels to detect the commercials is not always accurate; it is for this reason that I always disable automatic commercial skipping. I find that it is better to many skip the commercial than to have the program fail to play content without me knowing.
Unfortunately, in your situation by choosing to have Channels automatically skip commercials you are essentially telling the program you trust it to always make the right decisions. My personal experience is that is often not the best choice; you're decisions may differ.
You are talking about an old episode from Oct 2? It was a resolution and frame-size change when it switched over to the old norm macdonald clips. This kind of video switching is one of the things comskip looks for when trying to detect commercials. Plus there is no NBC logo for entirety of the weekend update segment including the old tape of norm. So there is really no better way for the commercial detection heuristics to work in the scenario. But it is accurate most of the time.