[ubuntu] Somone help with kernel / usb debugging?

I'm plagued by a usb problem. I have an exteal soundcard--a Topping VX2--that coects via usb. Under Ubuntu 15.04 and 15.10, the device worked as expected. But under Ubuntu 16.04, it causes severe problems:

1. When plugged in, the device often interferes with boot. Unplug the device, and Ubuntu boots as expected.
2. If left plugged in while booting/rebooting, upon successful login, all desktop icons and other theme-based decoration is reverted to the default Ubuntu settings.
3. If plugged in after successful boot and login, the device seems to nuke Pulseaudio: it wipes out all devices in "Sound Settings," giving the impression that there are no sound cards in the machine. Remove the usb cord, and all is well--my devices all retu.
4. During a reboot with the device plugged in, Ubuntu seems to hang and gives -110 USB errors.

* Thinking I had a defective unit, I retued this device for another one. However, the devices cause the exact same problems.

* The VX2 uses Via Technologies VT 1620A USB audio controller.

Could someone help me debug this and help me file the information as a bug against the keel? I'm not sure how to go about this.

Thank you.