I've been playing around a lot with the points and found that the problem isn't the double lines but the curves. Moho has a problem drawing lines pointy when exporting to svg:
While working on the lines break and thin out:
The corners I was able to "fix" by rounding everything with the curvature tool. The problem is I can't have sharp pointy objects this is destroying my lineart:
The workflow is just impossible. I have to export every change to svg to preview and repeat this process for every frame. While everything gets a rounded look.
About the double lines is it possible to merge them somehow? The only way I found to remove them is to completely delete all shapes and then recreate them. But even then doubles can't be avoided esp. in complex shapes it's not major problem but gets annoying when working with other software.
I was on Moho 12.1 and updated to 12.3 but the issues still exist:
