i’m experiencing this on mac but it seems like something that’s a core rhino issue as opposed to mac specific problem…
in top view,
if i use _Line -> Perpendicular…
set my start point (and lock it to that point with FromFirstPoint)…
the intersect snap won’t grab on to any curves that may cross its path.
seems like it should (or, maybe not? i might not be seeing the complete logic)
that said, there’s an easy workaround which is to press the tab key once the start point is locked in place… so not too big of a deal… but maybe someone can have a look at it.