The reason is that the Virtual UEFI core (OVMF) sets a random authority for the platform hierarchy (apparently as mandated by the TCG), so any attempt to create the platform primary fails with TPM_RC_BAD_AUTH. It looks like this is the commit in edk2 that caused it on 13 September 2021:

tianocore/edk2@610d807

So there are older versions of OVMF that don't have this problem, but every modern distribution seems to have picked up a version containing this patch.

I'm not really sure how to fix this, but the regression tests are useful to run in a VM, so it would be nice if the tests that rely on the platform primary could be replaced or disabled with a command line option so they would pass in that case.