That sucks! Sounds like it is time to do some swaptronics with the inshop unit. Neither one of those units are a killer swaps. Swaptronics replaces troubleshooting. If one fixes the problem, they can approach Polaris with a single unit fix. If either swap fails, back to pin out and sensor troubleshooting.
My best wishes to a quicker fix. Hang tough!
@NatomasSlingshot1 and @Ruptured Duck are the two worst cases I know of and are better equipped to answer any questions.