proxmox-backup-client failed: Error: EUCLEAN: Structure needs cleaning (500)

[harmonyp]

One of my PBS datastores are showing the following error across multiple nodes

proxmox-backup-client failed: Error: EUCLEAN: Structure needs cleaning (500)

What could be the cause of this? The datastore verify job passes

 

[t.lamprecht]

What's the PBS version in use there?

# client side
proxmox-backup-client version
# server side
proxmox-backup-manager versions --verbose