Big-IP not seeing all my users AD groups

Hi,

My access policy provide different portal access in a WebTop based on the users Ad group membership. The issue I'm seeing right now, is that some portal access icons doesn't appear even if the group membership is correct. I went in the report section, in the session variables, I don't see all the groups the users are member of.

The strangest part, if I add other groups to the user that have no link to my F5 configuration, some other groups start appearing.

Is there anyone who ever saw an issue similar to this one? Or, is there anyway to troubleshoot the query done from my F5 device to my Active directory?

Thanks, Jonathan