We hit the exact bug that was mentioned here.
https://bugzilla.redhat.com/show_bug.cgi?id=1378557
The issue was happening only with multiple AD domains configured and
trust established between them. libnfsidmap was stripping the domain
name if a username is passed in fully-qualified domain name format.
No-Strip option in idmapd.conf has to be set to "both" to stop
nfsidmap from stripping the domain name. Even with this option set, I
could not get it working with libnfsidmap-0.25/26. I could only get it
working with libnfsidmap-0.27. I compiled it, replaced both libraries,
libnfsidmap.so and nsswitch.so and username was properly being passed
to the layer below (sssd/winbind).
With this fix, id is properly being resolved with sssd and winbind.
Thanks,
Satya.