Past due sales orders are not consuming available onhand..

Hi Team,
Past-due sales orders are available in the plan, and on-hand quantity is also available. However, the sales orders are not consuming the on-hand inventory; instead, the system is generating new planned orders. Could you please share any inputs on this behavior?

it is a Constraint plan.

No lead time for items, on hand is not expired, on hand netting is enabbled.