I would rather not do this, I hadn't been using SwiftUIIntrospect until I ran into this problem, and I have a couple of cases where I map the slider's value to a non-linear range of values where this approach makes dragging the slider jumpy, but it's better (for now) than not rendering the sliders at all.

For other developers having this problem, since I'm just trying to draw a vertical scroll bar, I'm able to work around this by incorporating the SwiftUIIntrospect library -- I added the following to my Sliders when I want to render them vertically (it sets the isVertical flag on the underlying NSSlider instance): .introspect(.slider, on: .macOS(.v13, .v14, .v15)) { slider in slider.isVertical = true }

Yes, I am seeing the growing thumb button as well, at degree values which are not 0, 180, 90, or 270. The slider is rendered correctly at rotations of 0 and 180, disappears with the "CGAffineTransformInvert: singular matrix" message, and is rendered with an increasingly large thumb button with values between the even multiples of 90.