KVM VMs are restarted erratically

Hi all !
We are running a 2 Node HA cluster with quorum disk, and around 30 lvm-based VMs on a node. Two or three times a day, some of the VMs
are shut down and restarted by proxmox. Which VMs are affected seems to be random.

/var/log/cluster/rgmanager.log shows
at the beginning of the sequence.

To track this down, I extracted the code responsible for the message to a little perl script which fetches the list every second, but
the script always gets it correctly.

Any hints what to do or try ?

Thanks a lot for proxmox !