So mine was not used in any kind of jail.
I had 'Windows (SMB) Shares' setup and I could still login with the admin user accounts to the shares from Windows, it accepted the credentials but the shares were all read only I could not upload content, create folders etc. Rebooting the FreeNAS box didn't help, rebooting the Windows boxes didn't help. The share permissions when I looked at them in Windows had changed to GUIDs which is when you know something has messed up badly.
I simply removed and recreated the Windows shares in FreeNAS, for my purposes I've got about a dozen shares and five users so it took me 30 minutes to redo everything from scratch. Not a big deal but I can imagine for others this would be a real pain hence the reach out to see if it was a common issue with this version.
Can provide full spec's for my relatively new system but it's built from recommended parts, SuperMicro board, Xeon CPU, ECC RAM, 60TB disks etc. Been pretty happy with 11 so far. Hopefully it will run for many years to come.
My old FreeNAS was built from scrapped together second hand parts, no ECC RAM, 10TB and even that lasted 5 years. I was of course careful to keep other backups of anything important but it did it's job well.