"Are the SSO accounts you use to connect to the vSphere server also under this regime?"
Yes and those are the only creds we can use.
"In fact what do you enter to connect?"
Nothing........lol
Seriously, no creds used to log in for our rlevated account..
Here's how it works.
We have our regular account and our "Admin elevated" account is tied to it.
We have an RDP portal "Devolutions" or a web interface using 2 factor auth and we authenticate to it with regular user accounts. Once authenticated we can RDP to our "Jump server" that has all our tools installed. The portal automatically opens our RDP session using our elevated creds. We do not use type in username or password to the RDP session. It uses our elevated creds of which we do not know the password.
Now once logged into our jump server everything in there uses our elevated accounts and passthrough auth works for most everything that is designed to use passthrough authentication.
PowerCLI 6.5 worked fine before upgrading. The vCenter server and the platform server authenticated perfectly fine before upgrading.
Confusing........I know. :-P