

I feel like other things would have misbehaved if the power frequency was too low. And I’d expect the RTC to run well while power is on, and fail to accumulate time while power is off, but still remember the time at power off.
None of what I said above explains what we are seeing with our eyes though.

Unraid 100% doesn’t care about the order / slots.
I had some USB-HDD adapters of various brands. If it wasn’t going to survive a move and re-arrange, it already would not have worked. In my case, some of the USB-HDD adapters passed through the drive serial numbers and some did not. For the ones that did not, I couldn’t have more than one (because it couldn’t tell them apart).