For us it is important to keep the same encryptionroot on every server of the cluster as we use a keyphrase to unlock. Entering it as may times as we have vms on the server during reboot is not an option. Using a key is not an option for us neither - although I see cases where it is. So we had...
I had the same problem. In my case the DHCP-Server is part of a Windows Server. So I cheched my Windows Server DHCP. The MAC-Address in the lease looked like:
e08d289e00010001282adb7e9661e0aa289e
It should have looked like:
9661e0aa289e
So I created a reservation for the wrong mac-address...