Unable to default value in negotiation line dff from sql

Summary:

Hello Experts
We have a requirement to populate a default value in negotiation line dff. This value is derived using a sql query where we are checking the category Id of the line.
We have written this query in Default value of DFF configuration. But this value is not getting populated on to the DFF.
Surprisingly when we are using the same sql query for a requisition line DFF, its populating correctly.

Can you all tell, if you have faced a similar issue or if we are missing some step in the DFF configuration.

SQL Query:
SELECT NVL(b.attribute1, 'NONE') FROM egp_categories_b b WHERE b.category_id = :{PARAMETER.CategoryId}