In roman masters, the glyph components that are shrunk or enlarged uniformly will scale their left and right spacing equally. In slanted italic masters this appears to not be true. The shrunken components end up with uneven left and right spacing after being shrunken down, the effect get more noticeable the more you transform the component.
Here is and italic e as an example. As you can see from the images below it gets moved more and more to the right side as it’s shrunken down.
I fixed it. And found another place that needed fixing. But. I can’t put that in the 3.0.5 update (that is supposed to be released very soon) as it might change a lot existing files. But I’ll put it into the next bigger update.
Until then, you can use metrics keys. They are not as convenient but should get the job done. So you disable the alignment and use =e*0.3 (use the scale factor of the components) as a metics key on both sides.