[dmitch]

I can't give you much technical advice, but I can explain how our team, at least, troubleshoots electronics problems.

Our general rule of thumb:

We always swap out one part at a time, until we can locate the source of the problem, if that doesnt work, then it must be the code.

For your problem specifically, I would suggest a) put it back up on blocks to see if it runs on them consistently, and b) try swapping out the PWM cable that goes to the "bad" side with a completely different PWM. Since the DS must be working correctly, according to your post, then the problem may be that the signal isn't getting carried from there to the JAguar.