Dear MM team,
Once somebody created a delivery for the PO item, Committed date & few other details automatically recorded by system under "Delivery Schedule" tab. Also you see un-editable Committed Quantity within next columns that's because delivery has already been processed.
So if you can't see any delivery, it means that created delivery has already been deleted! (According to my knowledge that deleted delivery number couldn't see in any log)
Thanks & Best regards,
Charith