Interesting. I loaded up the Caravan today, both the Default Green I use and the Default Red just in case there's panel shenanigans, and in both cases the knob worked. It's a lot slower than I remember it being (and as we all know here by now, my memory is infallible 😉); the heading knob seems to rotate 1:1 with the heading bug, whereas the HSI course knob rotates a lot faster than the CDI, so it's possible I just didn't notice it yesterday.