I have the same issue (3 servers, all same behaviour), but cannot really identify the source - I migrated from 6.9 to 6.11 and simultaneously connected NFS share as main datastore for my VMs and Dockers (Unraid acts only as an application server for me, storage is elsewhere)...
My observation is that at this time period, remote file access is stalled - nothing seems to get through. When was using NFSv4 with remote locks, these locks were lost - effectively loosing file access forever and killing Unraid GUI into endless wait (maybe because of the lost connection to libvirt.img and docker.img?)... When switched to NFSv3 with local locks only, these protection faults still happen (mostly when some more intensive transfers happen), but with locks not being lost Unraid GUI will not freeze any more. But still, these dropouts are annoying.
And last but not least, what surprises me the most - process crashing that is being logged is lsof? why lsof, what is calling lsof at that time? cannot it be some plugin? or some stuff stuck from previous upgrades, my flash drives are quite old and all were updated from 6.9 to 6.11.x... why lsof??