AX 2009 SP 1 RU5, Weighted Average Inventory Closing Transaction Isn't Created

Hi all,

My customer run AX 2009 roll up 5. I’ve found one of their item which use weighted average (not weighted average date) as their inventory cost model which stop creating weighted average inventory closing transaction since May 2013 although after May, starts from June, there are many receipts and issues transactions. I don’t know why this is happened. Could someone explain it?