I am new to NFSv4, but I have it mostly working with my IPA (kerberized) domain. I just noticed that my nfs clients are not picking up the ACLs from the NFS server, that I set with the ACL Ansible module. So, I suspect the module is setting POSIX acls, not nfs4 acls. Is that correct?
That's correct, if you look inn the source code you'll see it only uses setfacl and getfacl.
If you don't use the extended features of NFS acls, you could set the ACLs on the NFS server and it will pick them up.