Intermittent overlapping brim generation for mouse ears  

Intermittent overlapping brim generation for mouse ears

Looking for suggestion on how to resolve this in case I'm doing something wrong here, before I raise a bug report for PrusaSlicer on GitHub.

I've been trying out the mouse ears as described in this video:

I've started seeing some of the brims generated by the mouse ears ignoring the object that I'm trying to attach them too, and generating brim underneath the object.

I try rotating some of the "mouse ear" objects and sometimes it generates brim properly (around the object but not under it), and other times it generates brim under the object overlapping the first layer.  PS warns of a conflict sometimes, but not always.

Photos to show what I mean:

Slab test object, created in PS (originally this is happening with a model exported as either STEP or STL from Fusion360).

The underside - zoom in on the mouse ears, and note that some of them are overlapping the slab object.

I rotated and recreated one of them and the pattern changed

zipped .3mf file showing this attached.  I have generated this example on both PC and Mac, PS v 2.9.4 on both.