CIFS sys_setgroups error

[Zach Zink]

We've upgraded CIFS server, along with a server migration, from A.02.04.01 to A.03.02.04.

Now, when a user with more than about 20 groups attempts to access our Unix server from Windows, they get a network error in Windows. Logging in /var/opt/samba/ shows this:

Group[ 25]: 50080
Group[ 26]: 50065
Group[ 27]: 50043
Group[ 28]: 50088
[2016/01/14 14:47:11.181752, 0] lib/util.c:1117(smb_panic)
PANIC (pid 18116): sys_setgroups failed
[2016/01/14 14:47:11.181791, 0] lib/util.c:1271(log_stack_trace)
unable to produce a stack trace on this platform
[2016/01/14 14:47:11.181831, 0] lib/fault.c:345(dump_core)
Exiting on internal error (core file administratively disabled)

So it seems like the newer version doesn't like users with too many groups, despite the config being ported over. 

Does anybody know any solutions?

Thanks.