This might be totally unrelated, but just to try;
Older Nuendo versions used to do this to me on a live gig, nonetheless.
But it was a desktop PC with RME ASIO .
Track count didn’t matter.
I could not figure out up to today…but the solution in my case was simple; after the “too many tracks recording”
warning I had to enter record again. Then all was fine.
Guessing the power saving/spin discs down, etc setting ( all were none) didn’t communicate to Nuendo.