Can you share the HID descriptor for the mouse? It should be found in /tmp, with a filename based on the USB vendor and deviceIDs (which you can find in the listdev command).
A syslog would also be helpful to see if there are any USB related errors.
I don’t think the mouse shows up in /tmp. I have three usb_hid_report_descriptor files, same device 0, 1 and 2. Boot with the mouse switched off, same 3. Those would presumably be the keyboard trinity.
I’ll file a bug and include the syslog. Only thing I see is “usb_hid: keyboard device unhandled control 0x00002710” I was just thinking there might be some obvious step I was missing.