slydog75

OK, it appears I have this issue fixed.   First, my CPU was definitely overheating becuase there was a wire stuck in the fan.. so I think that was exacerbating the problem, but I don't think it was the root cause; even after fixing that, if I transfered a file to cache while plex was playing it would still stutter.
 
I changed the transcode path from /mnt/user/plex_transcode/ to /mnt/cache/plex_transcode/ (appdata had already been changed to this previously) and that seems to have done the trick. SHFS no longer starts hogging the CPU whenever plex is recording Live TV and the stutters seem to be gone!