I'm not sure exactly when this started happening, but VMs no longer shutdown in a clean way, whether initiated from inside the VM or via Shutdown signal from Proxmox GUI. On a shutdown, the VM will hang, requiring a Stop command to be issued in order to shutdown the machine fully. Sometimes, even the stop command does not work, requiring a kill of the VM process from the the host. This is consistent across different OS on each VM (Windows, Ubuntu, CentOS).
pve-manager/7.3-4/d69b70d4 (running kernel: 5.15.39-2-pve)
pve-manager/7.3-4/d69b70d4 (running kernel: 5.15.39-2-pve)