This is a bug, not normal behavior. The most likely cause is a broken server action or automated action in your Approval module that loops and duplicates lines.

Quick fix to unblock your team:

• Create RFQs manually (not from Approval) – they work fine

• Then copy the manual RFQ instead of generating from Approval

To find the root cause:

• Disable all custom automated actions one by one on a staging branch

• Test after each disable. The duplication stops when you find the culprit

The integer field error when deleting lines means a broken reference is stuck. You cannot save because Odoo still sees the deleted lines in background.

Bottom line: Hire a freelancer to debug your Approval module integration – this is a 1-2 hour fix for someone who knows Odoo server actions.

Can i help - Yes, i can.

Hi,

The issue of duplicated products in purchase order lines when creating RFQs from the Purchase Request or Approval module in Odoo 18 usually stems from a conflict or error in how Odoo copies request lines into the purchase order. When the duplication occurs only on RFQs generated through requests and not on manually created POs, it indicates that the problem lies in the request-to-RFQ linkage — typically due to the _prepare_purchase_order_line method being triggered multiple times or a module override that duplicates the creation process.

The “invalid integer field” error that appears when you delete the duplicate lines happens because those lines are linked to a missing or invalid purchase request line ID. When you remove them, Odoo tries to set a required relational field to null, causing the constraint error. Checking in Developer Mode will reveal if the field purchase_request_line_id or approval_request_line_id is involved.

To fix the issue, review installed modules and custom code, especially anything inheriting from purchase_request_to_rfq or similar. You may need to patch the logic to prevent duplicate line creation or disable automated actions that might trigger extra entries. As a temporary workaround, manually recreate the RFQ, remove duplicates before saving, or export and reimport the valid lines. In summary, the problem is caused by duplicate triggers or broken foreign key links between the Purchase Request and RFQ lines, which can be resolved by reviewing custom module logic or disabling overlapping automation.

Hope it helps