USB is really not a reliable bus.
... i think the problems you describe come from the topology ,... apparently ( according to wiki/USB#System_design) usb uses '
tiered-star topology'
Or at least my problem with usb mostly is topological..
usblyzer.com/usb-topology.htmEven though the activity between the host and peripheral devices use the logical perspective, the host is aware of the physical topology to support connection and disconnection on hubs with attached devices. When a hub is removed, all of the devices attached to the hub must be removed from the host's view of the logical topology.