Thanks, I think I got them swapped to the correct order now with --gpu-map 0:1,1:0
I am guessing the REST issue is the card shutting down due to the overclocking and/or intensity level set to 5 on a computer that I actually use constantly. Weird that it's been fine for almost a year until now.
The REST was because it saw the temperature too high and was trying to cool it off - but since it had the mapping wrong, it actually shut off the wrong card, and the overheating one never cooled...