Affinity Designer Imports

When I import a composite image from affinity designer I get a negative (black becomes white) where the components overlap. How can I get rid of it?

What is the designer equivalent of ‘Object → Path → Outline Stroke’ (from illustrator)? Is it possible to add an addendum to your mini tutorial on importing to cover designer as well as illustrator and Inkscape?

Thanks

Open the Validation Toolbar (F7) to fix the contour directions.