Also potentially related to other users loosing their pool in virtualised TrueNAS, including when properly passing through a SAS HBA. Do I understand that you’re passing individual disks to TrueNAS rather than your SATA controller? Don’t do that!
Very curious how you get your pool back after reboot, as this might help others:
I’m inclined to suggest that the “solution” is to run TrueNAS bare metal and not virtualised on Proxmox.
Don’t do that!