Server Version#: 1.40.1.8227
Player Version#: 1.90.1.118-a4bc1429
This one is a bit silly but infuriating as edge cases go:
If you have a recording set to extend past its scheduled time (ie, a basketball game), it is literally impossible, as best as I can tell, to start watching that recording if you’re in the extra time of the recording.
It won’t appear in your DVR library until the recording completes.
You can see it on the DVR schedule page under Live TV, but you can’t trigger playback from that interface either. So it falls into some nether region until the recording completes.