When creating a promotion the customer can decide to which items the promotion will be applied.

One of the possibilities is to select the items by brand, including or excluding.

When trying to exclude more than 1 brand the following error appears on the UI: can't create search criteria! error: filter already exists:"brandId"

At the end the promotion will be created correctly and will be applying correctly on cartlinks, this error message is just a warning about the search on the catalog not being made as expected.

1. Create or enter a promotion;
2. Go to step 2 of the promotion and try to exclude more than 1 brand;
3. Verify the error message will appear.

Since this error has no side effects, except visual while saving the promotion, there is no need for workaround.