I've said this here before, but this thread is hundreds of pages now:
Tesla can't just replace a single module in a pack. The modules would go out of balance too quickly for the BMS to compensate due to unequal wear, degradation, etc. Unless they're very close in all metrics, it can't be done. Doing this at a central refurbishment facility is maybe possible if they have thousands of modules to choose from with their "fingerprints", so to speak, databased. This way they can maybe find a module close enough to the rest that it doesn't go out of balance immediately. But a service center won't be able to do a single module replacement inside a battery pack since there is just no way they'd have a matched module available to them.
To put things in perspective, my company is close to ~2000 salvage modules processed to-date... and, according to my testing database (which has data on a bit over the last 1000 or so), I doubt there were any that would have been compatible enough to be useful in a single module replacement situation. The closest mismatched ones would end up going too far out of balance after only a few months.