ATP confirmation

Hi Experts,

I am facing a issue where a SO-1 line item with RDD as 05/20/2020 is getting confirmed partially on 06/19/2020 and fully on 08/25/2020.

While SO-2 line item with RDD as 06/20/2020 is getting confirmed fully on 07/22/2020.

So my doubt is why the quantity was not confirmed for first sales order on 07/22/2020 because it is available for other sales order.

Ideally atp allocation would be first allocated to first sales order with early RDD. Please correct me if I am wrong in my understanding.

Attaching schedule line screenshots for both sales order.so-1.pngso-2.png.

This is not specific to any customer or material.

Please advise.

Thanks in advance :)