He says he's doing this on an M1 Mac's internal SSD. It's hard to imagine this would cause IO issues.
Interesting. It was something that was recorded during the diagnostics you had sent. I wonder if it was a fluke.
Just to verify something. When you've enabled hardware encoding and hardware deinterlacing, if you play a recording with transcoding, are you seeing it report 3-4x speeds in the DVR UI when you are doing it?