GSLayer.reinterpolate() has unexpected rounding errors

In 3260, it works fine, but I am getting a lot of rounding errors in 3414:

Hello, this is still an issue in 3418. Can this please be fixed?

Can you send me a file that shows the problem?

Sure. Here’s a test file. Note that if you set the LSB to an even number in both outer masters, the interpolation rounding error doesn’t occur.

InterpolationRoundingError.glyphs (1.8 KB)

Otherwise, you can also use the file I sent you via email last, and check the “Condensed Thin” master of the infinity glyph, as an example.