I have a very weird problem/bug!

A while ago I imported the Homeassistant VMDK via XOA and stuffed it into an (Generic Linux UEFI) VM.
It booted and runs flawlessly. Everything works - except backup via Commvault!
Commvault fails reporting the VM could not be found. Support found the following inside the logfiles:

4116  1984  05/01 21:00:29 58533 VSDisc::ProcessContent_VM() - virtual machine is not found using Name. Searching using both Name [HomeAssistant] and GUID [c3e276ed-1922-08a5-7f95-8b2d630e84ff]
4116  1984  05/01 21:00:29 58533 CXenSDKWrapper::GetVMInfoForVM() - Error:Getting VM information failed.Die Eingabezeichenfolge hat das falsche Format.
4116  1984  05/01 21:00:29 58533 VSDisc::ProcessContent_VM() - virtual machine: [c3e276ed-1922-08a5-7f95-8b2d630e84ff] discovery failed

I assume "Die Eingabezeichenfolge hat das falsche Format." would be "The (input) string has the wrong format" in english.

What I can: Discover the pool and select the VM to be taken into a backup job. So it somehow can see it, but it can't when running the actual job.
Here's where things go really weird:
I've spend quite some time, trying to narrow it down to a root cause. I've tried different VM templatesm, changed names and removed characters etc.
Then I've interchanged the VDI with another VMs. Surprise:
When I've interchanged HAOS VDI with a Debian Linux VMs OS VDI, the VM that cannot be backed up follows HAOS.
Means: Now The VM named "Homeassistant" is found and backed up, but the VM called Debian-Test is not.
So it turns out: Whenever a VM has booted HAOS, it can't be found during backup-discovery anymore. If it booted a "standard" Debian, the same VM is found again - until I change back to HAOS VDI.
The support was clueless and we decided that I should try it over here: It looks like HAOS has to change something at the VM "skeleton" / metadata, that it can't be found otherwise.

But how do I debug that further? How to find the difference and what exactly happens when it boots/runs?

Greetings

• Christof