I have exported testing volume:
/zen -nwmode -rw

All files on this volume owns user A. All IRM are SRWCEMFA.
On volume is directory /zen/read with RF rights for user B and another directory /zen/write with RWCEMF rights for user B.
User B has UID 365 and GID 210 in his unix profile. User B is in zam.fit context and in nfs.cfg is SEARCH_ROOT = .fit,.zam.fit
From Linux root successfully mount /zen volume, but user X with UID 365 has no permissions on it.

Why? What is wrong?