how to build a functional Windows Server 2022 lab in Azure Lab Services

I have created an Azure Lab template with Windows Server 2022 as the Lab machine. Equipment is 32GB main memory and 8 core for virtualization.

On this Hyper-V host I have created my Lab environment in the form of virtual machines.

First, I shrunk the "C" partition and created an additional 80GB "E" partition, which I could deduplicate.

Then I created 5 VMs on the E partition, with differential disks, starting from one VM as a template with sysprep.

So far everything worked - then created a lab pool with 8 machines.

This Monday morning everything went great for my students, but Tuesday morning brought the first problems. Certain VMs on the lab machines would no longer boot, booting in repair mode. On the Hyper-V server, the event viewer showed volmgr (volume manager) errors.

Tuesday at noon I re-published the whole Lab environment again, starting from my template. On Tuesday afternoon everything was running fine, all VMs on the Lab machines were running without any problems. But the same problem on Wednesday morning: VMs could not be started anymore, repair boot...

Since the lab environments ran without problems after publishing and re-publishing, only on the next day the problems occurred - I suspect that it must have something to do with the shutdown of the lab machines - but have no idea what...