Since baked lighting defines a unique lighting simulation per Texel ( pixel ) on your mesh, you need to be sure that UVs for your model do not overlap. If you have overlaps the baked results will overlap causing visual errors.
If your model has only 1 UV set then make sure those UVs do not overlap prior to baking into BRIO.
If you would like to use overlapping UVs as part of your texture workflow, this is fine but you need to make sure to create 2 UV sets prior to import into BRIO. For example, your UV set 1 can contain overlaps but UV set 2 needs to have all of the UVs for all objects non-overlapping.
Learn more UV preparation tips in our Light Baking Guide.