MAX_GID_LIST is a constant in clientserver.c with a value of 32. I have users who are in more than 32 groups, resulting in want_all_groups->getallgroups->getgrouplist failing. I'll just change the constant in my local build for now, but a way to configure the limit would be nice.
I switched the code from static-sized array to using a dynamic item_list struct, so now the gid lists can be as large as specified.