There are two things going on. First, the problem with CoreText I mentioned already. Second, the scale of components can’t be variated. The first two masters have a scale of 180%, the rest around 140. The default scaling of 180% is keep for all masters so the component looks to big in most masters.
The second master (Cp Th It) has a slant transformation. That is again not possible to put in a variable font, so the position is not correct.
So no direct bug in Glyphs. Maybe it should have warned about this…