Interpolation inconsistency

Glyphs
1

I am working on a typeface with 2 axes: width and weight.

When adding intermediate layers to control the proportion of some glyphs, there started to appear inconsistencies between what I saw in Glyphs and what happens when using typography on the Web.

Both images show the font at: width=350 and weight=350

Glyphs:

Screenshot 2023-09-19 at 16.42.38
Screenshot 2023-09-19 at 16.42.381570×964 24.6 KB

Web:

Screenshot 2023-09-19 at 16.42.14
Screenshot 2023-09-19 at 16.42.141844×1104 50.1 KB

Here you have the file:
RSTReactorSansVF.ttf (11.1 KB)

Is this a bug? I tried a lot of different stuff the last two weeks.

Hope you can help me.
Thanks!

2

You exercise the most control if you have a rectangular master setup. For brace layers, run the mekkablue script Interpolation > Add Missing Brace Layers.

3

I would not add more layers. You have too many already. Make sure you have all masters in the middle at wght 400 (and not 416).

4

I’ve tried both solutions and everything seems to work fine.
Now, I have two options to solve the problem. Thanks!