Improper values being returned

So I've been doing some work on a few things and I've noticed that if I check whether another character is in combat or not, when that character enters combat, the value returns correctly and it promptly updates to reflect their combat status, but when that character leaves combat there's a 5-6 second delay on Rebornbuddy noticing that they have left combat and Rebornbuddy reflecting that in the check. Some example code:

Code:

        public static BattleCharacter Pugilist
        {
            get
            {
                return (from battleCharacter in PartyManager.VisibleMembers
                        where battleCharacter.Class == ClassJobType.Pugilist
                        select (battleCharacter.GameObject as BattleCharacter)).FirstOrDefault();
            }
        }

And part of the behavior tree:

Code:

new Decorator(ret => Pugilist.InCombat && blah blah other checks here, 
    new Action(r =>
    {
        Logging.Write(Colors.LightPink, "Targeting...");
        Helpers.GetTarget();
    })
),

That part of the behavior tree still calls for 5-6 seconds after 'Pugilist' has left combat. Any idea why/can that be fixed?