~snip~
Good for you.

I haven't paid €300/stick just to put one aside accepting "this is how it is"...

I rather try to find an explanation why is one behaving so weird. There's a solution for everything. And yes, this is lottery and has to be fun not a struggle.
You say that 7 of them are working fine and the 8th one doesn't work properly, right?
Also that you're using the USB hub from GekkoScience?
https://i.imgur.com/oOCYxQD.jpgOne of the USB ports is designed to connect a fan, so it's power only.
That could be an explanation for your issue.
He made a typo I guess and he's using "2 Gekko hubs", if I'm right.