If your NPC/zone is staying up, have you tried to undefine the globals. Obviously it won't effect the database. 
 
Here is what I have seen before. I had an NPC delete a global, but the global still existed until it was undefined or the zone/NPC was reset. I am thinking that it might be somewhat related. 
		
	
		
		
		
		
		
		
		
		
		
	
		
		
	
	
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