Verified using version: 
sssd-1.16.0-19.el7_5.8.x86_64
ipa-server-4.5.4-10.el7_5.4.3.x86_64
389-ds-base-1.3.7.5-27.el7_5.x86_64
krb5-server-1.15.1-19.el7.x86_64

Verified the bug for FIPS mode and NON_FIPS mode

Console:
------------ 
:: [ 06:40:59 ] :: [  BEGIN   ] :: Running 'service sssd stop; rm -rf /var/lib/sss/{db,mc}/*; service sssd start'
Redirecting to /bin/systemctl stop sssd.service
Redirecting to /bin/systemctl start sssd.service
:: [ 06:41:02 ] :: [   PASS   ] :: Command 'service sssd stop; rm -rf /var/lib/sss/{db,mc}/*; service sssd start' (Expected 0, got 0)
:: [ 06:41:02 ] :: [  BEGIN   ] :: Running 'sleep 60'
:: [ 06:42:02 ] :: [   PASS   ] :: Command 'sleep 60' (Expected 0, got 0)
:: [ 06:42:02 ] :: [  BEGIN   ] :: Running 'getent passwd 'IPAAD2016\Administrator' > /tmp/tmpout.ipa_trust_func_bug_1034920 2>&1'
:: [ 06:42:02 ] :: [   PASS   ] :: Command 'getent passwd 'IPAAD2016\Administrator' > /tmp/tmpout.ipa_trust_func_bug_1034920 2>&1' (Expected 0, got 0)
:: [ 06:42:02 ] :: [  BEGIN   ] :: Running 'sleep 30'
:: [ 06:42:32 ] :: [   PASS   ] :: Command 'sleep 30' (Expected 0, got 0)
:: [ 06:42:33 ] :: [  BEGIN   ] :: Running 'cat /tmp/tmpout.ipa_trust_func_bug_1034920'
administrator:*:1577600500:1577600500:Administrator:/home/ipaad2016.test/administrator:
:: [ 06:42:33 ] :: [   PASS   ] :: Command 'cat /tmp/tmpout.ipa_trust_func_bug_1034920' (Expected 0, got 0)
:: [ 06:42:33 ] :: [   LOG    ] :: HOMEDIR /home/ipaad2016.test/administrator expected


With the above observation, marking bz as verified.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:2756