This was discovered while fixing this issue . The scale defaults to (expected_icon_size / 2) / icon_size which makes the icons too large for the map view.
expected_icon_size defaults to 64 for recipes but the correct scale appears only when expected_icon_size is set to 32 for the recipe.

expected ...

Oh nevermind I found the issue. I accidently left my aircraft on some inserter which then inputs into the aircraft and when I left it on inserters pulling out it then messed the belt up. Thanks anyway.

An belt (Fast transport belt) with iron plates runs directly next to a belt (Fast transport belt) with copper plates and there is no chance the two merge somewhere. But after some time I notice that there are a few copper plates on the iron plate belt.

Installed mods:
Aircraft
Aswil
Better long ...