Is Ubuntu a bad citizen in an Unraid server?

Hi, I have an unraid server, on top of which I am running a number of VM. One of these, an Ubuntu one is behaving as a bad citizen, meaning that upon shut down it does not release a number of resources,
The situation is so bad I cannot even restart the same VM as its resources would not be free from the previous run and the only way to “restart” ubuntu is to reboot the server.
Has anybody experienced anything similar? any tip for a script to “clean the mess” after the linux VM has been shut down?
Thank you for your help

works fine for me.

image

I’d post over on the limetech forums though. if you’ve found a bug, they will want to know.

are you able to stop and restart those machines with no problems? do you pass through to any of those system any pci-e device?

I am not doing any passthrough, they restart fine though.