Variable Font with Corner Component

Hi, I’m trying to export a variable font from Glyphs 3. The font has Corner Components, which are set up like described in the tutorial. Both the Corner Components, as well as the base Glyphs are compatible. Still I’m getting this error:

How can I solve this?

What version of Glyphs do you have?

And can you show screenshots from the ‘b’ masters?

I’m working with 3.0.3 (3089).
This is the b in all masters:

The corner component is set up like this in all masters:

I don’t think it is caused by the corner.

Can you show the same for the bowl glyph?

Sure. The bowl glyph seems compatible too

Looks good. Can you send me the file?

The problem is with the corner component after all. The top “_corner” is slightly to large and crates this little spike that produces a self intersection.

move those two point one units to the right or make the stem in the ‘b’ one unit wider.

Ah I see! Thanks @GeorgSeifert