IIRC there is currently a bug / bad design decision in proxmox where it auto-imports zpools into the host OS. If the zpool is currently imported / in use in a guest as well this will cause pool corruption. ZFS is not a clustered filesystem and so it cannot be consumed by both host and guest simultaneously.
IIRC the only way to avoid the data corruption is HBA passthrough. @HoneyBadger has more details.