I also had this kind of symptoms with nautilus.
Replacing a failed disk (from cluster ok) generates degraded objects.
Also, we have a proxmox cluster accessing vm images stored in our ceph storage with rbd.
Each time I had some operation on the ceph cluster like adding or removing a pool, most of
our proxmox vms lost contact with their system disk in ceph and crashed (or remount system
storage in read-only mode). At first I thought it was a network problem, but now I am sure
that it's related to ceph becoming unresponsive during background operations.
For now, proxmox cannot even access ceph storage using rbd (it fails with timeout).