When attaching corner components to extra nodes, the corner components behave very erratically once you start doing anything with shapes of that glyph. They attach themselves to other nodes, replace other corner components etc.
Fixed it. It seems that it is a problem in Glyphs 3, too.
Thank you Georg!
(it was to less extend in Glyphs 3)
Still seems to be an issue. Not to the same extend though.
See the video:
Can you send me that file?
Sent