In attached link MRP type comes in picture when system is not able to determine ReQ Typq but in this case for both of materials same requirement type exist in sales order, even availability check rule is same in materials. Item category is same too.
The only difference is schedule line category in sales order - CN (No MRP) for material which has ND type while other has CP (MRP) MRP type PD
Does CN or CP has any control on ATP?