Have a look at the two images below. The model is the same, the GL configuration is the same, the style is the same, but they look very different. In the one taken from 2018, the look is the same as it always has been. In the 2019 view, the lines appear too thick, as if there was a difference in style, but there is none.
The odd thing is that if I close 2019 and reopen it the problem goes away, at least for some time.
What could be causing this?