If this is not a TMCC lashup, then how is an address in the 90 range being used?"
I believe the remote will use them when it's nearly full.
I have MTH engines loaded in the 90s. I believe I have consists too. I would have to confirm this. I never noticed this issue popping up. The key here might be that I don't have any TMCC engines loaded?
or maybe I didn't run the consists for more than a session?
I (or anyone here) would have to try it and report back.