Hello Gecel,
Could be due to purchasing policy setup.
Can you check in Purchase requisition RFQ rules and see if you have set any specific criteria for requiring a request for quotation for a purchase requisition line?
By default; it will be always set to Never.
Please check if setting up "Never" here is actually solving this case or not.

Is that issue happening for all users or any specific user? Have you checked by logging in with system admin user?
Also make sure that below roles have been assigned to the user (who is Not a system admin) who is facing this issue.
--- Buying agent
--- Purchasing agent
Kindly check and update in the Forum.
Best regards,
Sourav Dam
Kindly mark this thread 'Yes' if this is answered your query which may help other community members in this forum.