Hi,
Not sure but it is entirely possible that when you connect the USB3 device directly into the VM that either the Windows XP stack or VMware's usb logic gets confused and ends up in a broken state that can only be resolved by rebooting the guest.
FWIW I have never read about anybody who was able to use USB3 within an Windows XP VM successfully. Yes I have seen some claims, but I'm fairly sure that those devices simply negotiated down to USB2.
--
Wil