Item Description Updated On closed PO Lines After Change While 'Allow Description Update' Attribute

EBS 11.5.10

1.Item created and Description set

2. MASTER ITEM 'Allow Description Update' Attribute set to no(unhacked)

3.PO created approved apply all cycle and close

4.item description changed on master item(after the PO been closed)

5.The new item description reflects on closed purchase order lines being created prior to the item description update

I would expect update on non closed \ cancelled lines but history wise for closed and cancelled is being overruled.

Is that the expected behavior?

Regards,

Miki