I tested with a USB 3.0 thumb drive and adding that works to the guest works perfectly.
Here's a shortened lsusb:
Bus 002 Device 002: ID 0951:1666 Kingston Technology DataTraveler G4
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 007: ID 059f:106e LaCie, Ltd Porsche Design Desktop Drive
.
.
.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
So the Kingston in the USB 3 HUB works, but trying to add the older USB 2 drive to the guest fails.
The laptop is new, and has only USB 3.0 ports as far as I can tell.
I tested with a USB 3.0 thumb drive and adding that works to the guest works perfectly.
Here's a shortened lsusb:
Bus 002 Device 002: ID 0951:1666 Kingston Technology DataTraveler G4
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 007: ID 059f:106e LaCie, Ltd Porsche Design Desktop Drive
.
.
.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
So the Kingston in the USB 3 HUB works, but trying to add the older USB 2 drive to the guest fails.
The laptop is new, and has only USB 3.0 ports as far as I can tell.