Yes, me too actually. But I was experimenting with the new Primaries module in the Windows dev version, which I haven’t set up as my proper production editor. So, color calibration was on by default, and that bit of gamut compression caught me out.
You’re right, it’s not a total waste of time. I always learn something new when I go down these rabbit holes, but sometimes I get even more confused. Like, I thought sRGB was by definition bounded, but it turns out you can have unbounded sRGB!