Hi Lee, Just checked and can confirm that I do see a mix of live and replay.
Replay with ADSB Rx Connected
Replay without ADSB connected
It's difficult to check what you see on Skydemon. I made a note of some obvious callsigns and positions, then started to replay a track. The live aircraft remained, as well as the playback traffic. Yanked out ADSB Rx and live traffic disappeared after a second or two, but the playback traffic remained. The symbol for my aircraft was in the correct location for Live (Home) and playback (Enstone) phases.