Currently, we have two behaviors for the refid code, via API it is not possible to be the same as other products, but via UI it allows us to insert the same value as other products already have.

Create a product with a redIf code Create another product and try to use the same refId code as the other one, via API it won't be possible but via UI it will.

If you need to use the same refIds for different products, insert them via UI.