I'm not sure if this is a Roamio Plus/Pro bug or some weird SDV side effect.
Situation: Roamio is tuned to the same channel on multiple tuners.
Observation: Roamio thinks it is recording a program while this single channel is active on multiple tuners. However, the channel being "recorded" indicated by the red circle has only a black screen with no audio. The other tuners on that same channel display normal video and audio.
If I cancel the recording on the "black" tuner channel, the video and audio are restored without having to re-tune, but obviously nothing was recorded. I've seen this at least three times during the last week.