Source agreement automatically populated in a non-catalog requisition

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Source agreement automatically populated in a non-catalog requisition

Content

Hello,

I want to understand the following behavior:

1. User performs a non-catalog requisition, specifying a suggested supplier.

2. When the purchase requisition is submitted, the system automatically populates the field agreement, with no user action.

Why is the system populating an agreement if the user has not performed this action? 

It populates always the newest Contract Purchase Agreement?

Please, I need to understand the logic behind this behavior.

Regards,

Eric