I ran into this same issue and was never able to solve it. Other USB game controllers I've tried also exhibit these symptoms. I bought a PCI-E USB card and passed that entire device to the VM to solve the issue.
Thanks for the reply. I use autofs for Ubuntu to mount the exports. The symptoms (NFS crash) also occurs with my Mac, so I'm not thinking this is a client issue.
NFS consistently crashes with different shares and clients (MacOS and Ubuntu). It seems I can make it crash very easily with Attached is the diagnostic report.
I'm a new user, and I'm in the process of migrating my data disks from BTRFS to XFS (encrypted) based upon feedback in the forums and my use case (mostly Plex). I'm not sure that's the cause of the crash (this happened when i was all BTRFS as well), but I thought I should add that info
unraid-diagnostics-20180919-0959.zip