I had nearly the same issue on the same session.
I stopped exactly where I should have. I then uncoupled the helper engines in order to set them in the siding but it continued to show that I had NOT uncoupled them and showed that I was not in the correct place to uncouple them.
The uncoupling has to take place in the correct position in order for the stop hand to appear on the siding where the helpers need to be parked. Since the train is long and the "slack" can be significant from one end of the train to the other, I tried to use the rear driver/engine to position the train properly for uncoupling. While doing this, it caused the front of the train to run the red signal and I too lost all my points.
I have had similar issues with several sessions, not just the Mojave. It can be frustrating because some of the sessions are quite long and it really burns to fail at the very end. I had tried to save the sessions at points along the way so that in case something goes wrong, I could then load the session before the error took place and try again. I have found this does not work because when I reload the session the entire point system is gone (the starts, points, and timer). While I can continue and finish the session, no points or stars are awarded.
While I don't consider myself a "cheater", I have tried to modify or edit the session rules in a couple sessions and then save the session under another name in order to try them again. It resulted in awarding me the points and stars throughout the entire session but does not credit them to my total stars after the session is closed and I return to the main menu. Perhaps I just don't know how to do it correctly.
I may try the session again when I have time. If you figure it out, post it here.
John
