This is a feature I’ve only just started using, so may have nothing to do with the recent change to the devices widget.
When I click “attach to qube” for a device that’s already attached to a different qube, it will detach it, but about half the time that won’t have completed before it tries attaching it to the new one and I get an error notification saying it’s attached to the original qube. It’s only taking a couple of seconds to detach, nothing unusual I can see.