True. Well, I guess I'm out of ideas, even long-shots. Hopefully someone will come along soon to give you some more insight. Good luck!

 

I solved the problem!
When I said I removed the key - it was still loose in the dash slot, but nothing was on. I've always assumed that it did nothing once all the dash lights went off and windows didn't work, etc. and was a safe place to keep it while in the garage. So when I was towing I left it loose in the dash.
This trip I put the key in my pocket and the odometer didn't register.
I'm sorry I wasted so many of your collective brain cells!

 

Huh! Well, glad you finally figured it out.

Odd the car would behave that way with the fob loose in the receptacle, but odd behavior can result when you're doing something 'non-standard' to how the software programmers thought the vehicle would be operated...

 

I know-really odd, especially when I was coasting down the driveway with engine off, key loose in the slot and the dash was lit up like it was running.

 

Just so you know there is a in tow setting in INPA BMW software. Not sure what it does but in your case you may need to use it.

 

I don't know how I'd access that but my issue has been resolved by removing the key completely. I'm using wireless magnetic tow lights so now have no electrical connection to the motorhome.
My little Clubman tows so nicely I wouldn't know it was back there if I couldn't see it in my rear view camera monitor.