So odd...I work with customer who has AD query enabled WITH IC as well and no issues at all. Mind you, I believe TAC recommends to turn off AD query if you use IC (which makes sense), but either way, it should work, 100%. Do you see any logs related to this on your AD server at all?
Below is what TAC gave me once to debug identity awareness issue, so this also might be worth a shot.
(•)•) Identity awareness debugs
# cd $FWDIR/log
# rm pdpd.elg.*
# echo "=debug_start=" >> $FWDIR/log/pdpd.elg
(•) To turn pdp debug on:
# adlog a d on
# pdp debug on
# pep debug on
# pdp debug set all all
(•) Replicate the issue
(•) To turn them off:
# adlog a d off
# pdp debug unset all all
# pdp debug off
# pep debug off
# pdp d reset
# pep d unset all all
Collect debug:
$FWDIR/log/pdpd.elg
# tar zcvf pdpd_debugs.tgz pdpd.elg*
# tar zcvf pepd_debugs.tgz pepd.elg*