Updating Slider from Mod Wheel

I’m designing a synth, and I have a slider on the synth representing the mod wheel. I want the slider to move up and down when I move the mod wheel on my midi controller. So I’m calling the setValue function from within my synth object’s controllerMoved function. Working great, but I’m getting an error:

This only happens once, the first time I move the mod wheel. Not sure what this means. Would it be blasphemous for me to leave it since everything’s working correctly? Or am I asking for trouble leaving this error?

Well, that sure ain’t my code!

Assuming that you’re not doing any obj-C hackery yourself, then this will either be a bug in the host app, or somewhere deep in the Apple Cocoa libraries. I wouldn’t worry about it if I were you.

Good. Thnx.