Why is the brim happening in these holes?

I need a brim on this model since it’s so tall. So I set the brim type to outer brim only, but when I slice it it fills in the holes too. How do I get the brim on the outside of the model only?

if you paint the preview with “Line type” display, you can tell for sure, but I think they are supports, very small ones, for those drillouts. You can mark the area as red in the support painting tool to suppress em

ahh…That is a support! Thanks.