We're using rfc2307 schema and default ldap_group_object_class value
(posixGroup). Besides that, I don't see what could explain that you can't
reproduce the problem. Chris Petty is using AD hence rc2307bis schema. So I
don't know if it is relevant.
Just to sure, did you log as root (no sudo), stopped sssd, cleanup the cache,
restarting it (all as root without sudo), and ran the script (as root) ?
# (logged as root)
# /etc/init.d/sssd stop && rm -f /var/lib/sss/mc/* /var/lib/sss/db/* &&
# python initgroups.py jbdenis 110 5 24 200
Sometimes I have to perform these steps multiple time to catch the problem.
Did you have a chance trying again if you didn't follow this modus operandi
(everything as root, no sudo) in your previous attempt ?
Since Chris Petty managed to reproduce it with the script with in a different
environement, I'm quite confident that we're on something here.