yup, same issue
I got the parameter mapping and the external assignment working just fine, but when I turn the knob it jumps straight from -5000hz to 5000hz on the frequency knob.
I'm using an iphone app called "knob lab" if you're familiar with it, but again I wasn't having this problem the first hour or so of using it. I checked the settings on the app itself, but there's nothing there that would mess things up. That's why I think I accidentally clicked on something weird, but I couldn't say for sure.
All the same, I still learned something today! You are appreciated sir.