ATP "One-Time" button rejects all quantity,if my route has a lead time

Hi all,

We have activated transportation scheduling in our SAP environment. I have experienced below behavior in our system. Appreciate if you could let me whether it is the standard SAP behavior. If yes, what is the reason behind it?

From the material "ABC", I have only 100 quantity in stock. When I create a sales order for Sold to / ship to "XYZ", the route is determined with 20 days lead time in the sales order line item.

Scenario 1: Route is available in the SO/LI

If I enter sales order line item quantity as 150, and press the button "One-Time" from the ATP screen, all 150 is rejected with the rejection reason "J2"

Scenario 2: Manually delete the route in the SO/LI (NO route available)

Now if I enter sales order line item quantity as 150, and press the button "One-Time" from the ATP screen, only 50 is rejected with the rejection reason "J2", rest (100) is confirmed with the correct lead time.

Any idea why this behavior?

Many thanks in advance!

Best regards,

Rahal