Next time when you have a similar problem please request the following
Check : The Production Order.
Production Order: Make sure the Status of Order is still OPEN.
Order lines (the part at the Bottom): Make sure the Product is part of the Order lines
Status: IS still available
Max Amnt: In this case it was 11
Current Amount was 10 when logged in, so they packed the last one then it went to 11 then changed status to 11
So I guess when they packed the last item it closed the PACK and order was complete