I think the version is relevant. We just updated to fog-vsphere 3.6 which switched from rbvmomi to rbvmomi2, but that's only in nightly. You do mention develop, but can you also verify rbvmomi2 is used? I believe that uses the vmodl.db file to provide the definitions.

The mapping list for OS versions that this updated list relates to is still hardcoded in Foreman code - a.k.a. https://github.com/theforeman/foreman/blob/develop/app/models/compute_resources/foreman/model/vmware.rb#L232-L398
Not sure if it's possible to generate it, since the upstream documentation fails to do so for any vSphere newer than 6.7, but getting the descriptions off of a running cluster proved doable.

It's likely that an updated vmodl.db will help as well in regards to the cloning issues, but I've not been able to actually test that yet. I might be able to look at further tests on our local systems some time next month, but until then the updated description mapping remains attached here.