In Glyphs 3507, rotated components with TT instructions are not exported correctly.
My bracketleft has TT instructions (see image), the bracketright is a rotated component, which gets automatically decomposed on export. I believe this is the standard practice.
Glyphs 3506 exports the TT instructions correctly, Glyphs 3507 gets this wrong.
Of course, I only found this because I spent half an hour of TTXing after updating Glyphs, as I typically do, just to check for possible new bugs. I really wish this wasn’t necessary. Can’t we get updates that only fix bugs without introducing new ones? It almost feels like the whole thing is moving sideways.
Glyphs 3506: 
Glyphs 3507: 
