Active Roles 6.9 admin service over load balancer

we have two admin service behind F5 load balancer..  Users are experiencing error 500 often.. The error goes away if we hit BACK and re-attempt the task. This is annoying. One identity support says ARS is not tested to work with load balancers but functionality works.  We don't see error 500 if we access the server URLs directly. Any of you setup the admin service behind LB?  If yes, are there any recommended settings that we should try on the LB?  Note: we tried enabling cookie persisitence on LB but the entire ARS app wouldn't load thru LB with this setting.