Fillet vs. Fillet Distance... Unexpected behavior

I’d really like to use fillet distance, however it doesn’t seem to want to do anything with some of my closed curves that were made with Brep | Brep.

Fillet gives the expected result, in terms of not ignoring the shape altogether, I just want the setback fillets instead of radius fillets.

Is there any trickery I can apply to the problematic curves to make Fillet Distance accept them?

EDIT: Specifically it’s when the intersection has any curvature. If I Brep | Brep planar surfaces, Fillet Distance seems happy to work with that result. It’s just when one of the inputs has some curvature it stops working.