Wait, okay - this is why. While it’s capable of running an OS, it can have issues with power suspending on the USB side of things. I’ve seen this before.
Best use case for the expansion cards in my experience is for data backup (ideal and worthwhile). It “can” run an OS, but your mileage may vary.
The only time I’ve seen really bad issues like this is when the system tries to suspend (running Linux on an expansion card) and that usually results in a fault.
So if it’s not suspending, it should be fine and trying the above suggestion I made would be the next step.