VF master flipping upside down, scaling, and reversing position within em square upon export?

hi—I’ve found a weird thing that I can’t explain at all. this is a variable font with six masters (3 for text, 3 for display). here’s how things are set up in the design file:

but in the generated file, this is happening, only in the 5th master (which is analogous to Display Light):

it’s happening in every character, thankfully, which points to a fairly simple error happening—but I’m not sure where to even begin diagnosing this one. I’m absolutely positive I’m missing something. help?

This was discussed just a few days ago: Issues with Variable font export - #8 by GeorgSeifert

aha, there it is. I knew it’d be a parameter setting. thanks, Georg.