Source of supply not populating in MRP generated PR for contract

When I run MRP, it creates the PR, BUT, it doesn't assigned source of supply automatically.I can assigned it manually by clicking "Assign source of supply"

Why can the MRP assign it automatically, even i maintained source list with contract number. I don't have any other vendor assigned for this material in the source list

Can you please help? Here are my setting:

Material masteru2022

Procurement type = F

u2022 Source list indicator is checked

Source List

08/02/11 To 12/31/11 vendor xxxx Porg xxx Agmt xxxxxxx Fix (Checked) MRP = 1

**Contractu2022**

Document type MK (Quantity contract)

Agreement date 8/4/11 validity End 12/31/11