Update Stategy for Proxmox VE?

Hello forum,

I have built up a Proxmox VE cluster using two servers with mirrored storage (DRBD).
Btw: this is only @home for testing etc., so nothing business-critical or such things ;)

Now: Earlier with VMware ESXi / vCenter, we did the updates of the hosts like this:

1. Move all VMs to Host 1 (Live Migration)
2. Set Host 2 to maintenance mode and install updates
3. Move a non-critical VM back to Host 2 and see if everything is working as expected
4. Move all VMs to Host 2
5. Set HOst 1 to maintenance mode and isntall updates
6. Move a non-critical VM back to Host 1 and see if everything is working as expected
7. Move a part of the VMs to Host 1

I have tried to do this using Proxmox VE, but after updating the first host, I cannot move back any VM back to this host using live/online migration: the VM is just powered off (Task failed)!

Now: what would be the correct update strategy in a Proxmox VE cluster when used in a High-Availability environment?

BR,
lousek