Windows 10 VM suddenly BSODs

I have a Windows 10 Hyper-V VM running on a Windows 10 host.

• Until yesterday, everything worked fine.

• Since yesterday, the guest VM bluescreens with an error code 0xc000021a immediately after starting.

• Resetting the VM to an earlier snapshot (taken months ago) won't fix the issue - the same BSOD occurs.

Thus, I can only think of two possible reasons:

• Some new problem on the host (unlikely, since all other VMs work fine) or
• some undetected bit flip in the base vhdx file (which, according to the NTFS modified date, has not been touched for months).

Are there any other possible explanations that I am missing?