Pricing Rule Error in Mixed Condition

Created Promotional Scheme in on Item Group “mixed Condition”
Min Qty Set 25
once we Make delivery Note for Item A - 10, Item B - 10 & Item C - 5,
Scheme is calculation perfect.
but
when we Press Submit Button come to know that Item C is Out of stock, After we delete item C at the time of deleting Scheme should also be removed as mix conditoin not match but Currently system catches the Scheme which need to be fix