Incompatible corners

I’ve got an issue with some corner components that I can’t figure out how to solve.

I’ve got two masters in my file, but glyphs seems to think that there’s a third master, and is flagging outlines which would otherwise be compatible as incompatible.

Here’s a screenshot of what going on:

There has never been a third master in this file, so I don’t understand what’s happening here.

Can you share a screenshot of the Layers palette for this corner glyph?

Sure, here you go:

Can you send me that file?