I can’t think of a good example, but I know I’ve seen it quite a bit. In episodes of shows that have a “reset button” so that each episode starts from the same place, and episodes can be pretty much shown in any order; but not including deliberately absurdist shows like 30 Rock or Futurama, which episodes ended with the most apparantly unresolvable situations, that were never bought up again?
I doubt it qualifies, but the ending of Season 1 of “Martial Law” had Chow Yun Fat falling out of a helicopter and Kelly Hu was being kidnapped in said helicopter, but when Season 2 started, it was like, “What helicopter? I didnt see no helicopter!”