I looked into this (posted also on the SketchUp public forum). Reposting here where TIG keeps the actual extension and has the main discussion about it.
I reproduced the issue on macOS Ventura 13.3.1 on my Intel-based 2019 MBP 16" using both SketchUp 2023.0.396 and SketchUp 2022.1.165. So it is not specific to Apple Silicon nor to SketchUp 2023. I don’t have a pre-Ventura version of macOS running, so I can’t verify whether the issue also happens on Monterey or earlier.
After some testing, I found that the extension was looping in the draw (view) method after the second point is picked (in the @state > 1 clause.) I think the problem is that the code calls view.invalidate from within the draw method, triggering an immediate call again to draw - endless loop! I commented out the view.invalidate, and the problem went away.
I’m not clear why the view.invalidate was needed in the first place, even on Windows. @TIG, perhaps you can explain? If it is needed on Windows or older versions of macOS, a simple branch test based on OS version could fix it?