I noticed an unpleasant bug when you adjust the alignment of the line on the inside, each time the fill color appears on the contours if the outline is not the same color it can be seen very strong in the high contrasts (as on my example). I also notice that this artifact appears on export in any format. This artifact always makes about 1 px.
I'm not the only one to have this bug since I discussed it with somebody on a group facebooj affinity designer and one of the members immediately did the test but this time with the desktop version and there is exactly the same problem. Hoping for a correction in the next update, thank you already for the answers.
Ps : effects or gradients etc.. don’t affect this problem. Simply draw a red circle with black contour and a black background plus stroke alignement on intérior 2 icon like on image and voilà you see the artifact