Artifacts on paths with Bevel

ChrisDSA

I have this strange effect on my maps: When I apply the sheet effect bevel, I get no smooth surface, but these strange craters.
The artifacts are different at each zoom level. But when you save the image as JPG or in another raster format, the strange forms are also to be seen.
The path is not combined. There are no other effects on the path. The effect seems to occur only with bitmap fillings.

My question: How can I avoid this?

Monsen

This is a side effect caused by how the bevel effect detects the edges of the entity. What happens is that there is a pixel on the sheet below with exactly the same color as a pixel in the current sheet.
The best workaround is to insert a new sheet between those two, and put something on a very different color there, for example a pink copy of the same entity.