Bracket Layer + Kerning + Variable Fonts

There seems to be a bug, when I use bracket layers for a Variable font. Glyphs switches the kerning values of the two masters.

So what happens is: The glyph is switched to the bracket layer glyph. (NICE!)
BUT: The Kerning values of Master 1 (of this particular glyph) end up in Master 2 and vice versa.

Which precise build of the app? 1280?

1280 it is.

Can you send me the file?