Another few bits - the certs are ECDSA (not RSA). I wonder if there’s some process that breaks if that’s the case.
@JamieG Have you tried one configuration profile with a single certificate payload for all certs? Have you verified that Keychain Access can import the cert files used to create your certificate payload?
Narrowing down on my issue - for some reason, our RootCA, is not recognised by macOS as a Root (e.g. the orange certificate), instead it's recognised as an Intermediate... (blue certificate)
I have no idea why this is happening, but that would make sense for the rest of the problems.
So what makes a root a root? It's seen as it's own issuer etc.. and we haven't seen any issues in our Microsoft AD world.
EDIT: Removed non-useful suggestion
Got to the bottom of the issue - turns out our RootCA was using specifiedECDSA which a lot of stuff doesnt like, changed it back to sha384ECDSA as it should have been (not the MIcrosoft frig on it)