NFS service not starting after reboot

I have a weird anomaly I'm trying to figure out with the NFS service.

The NFS service is enabled on several of our RHEL 7 servers, but the service doesn't start up after a reboot.
If you manually restart it with "systemctl start nfs.service", it fails the first time, but if you immediately re-run the command it starts right up without issue.
I suspect the same thing might be happening on reboots, but the system doesn't try a 2nd time and just leaves NFS in a failed state.

Any ideas?

PG