Thanks ! This really worked like a charm. Had about 55% of the products rejected for GTIN. Now all is solved.
For other people, how to do this:
- Go to GMC / Products / Feeds
- Click on the feed (feed name)
- Click on “Feed Rules” (in tabs above)
- Click the “+” sign to add a feed rule and select “brand” (under ‘processed attributes’)
- Select “Add Modification” (bottom left)
- Select “Advanced Operators” and scroll right to see the “Clear” option. Select it and click “ok”
- “Save as Draft” => “Apply”
- click “Re-Process Feed” (above right - if you don’t see it, go to the tab “Processing”)
Depending on the amount of products, it can take up to an hour. But then this issue should be solved for all products.
These feed rules are very powerful. And you can’t make permanent mistakes because you can always delete the feed rule and reprocess 