I have a new QS switch coming from Bazzaz. We'll see if that fixes the problem.
While I was about 4km into a 10km run a few days ago an idea popped into my head. I got home and opened up the Z-Mapper program and went to the QS tab and checked the cut times. Well, it turns out that you can actually set the cut times for each gear to zero. Knowing that, I can load the same fuel map and TC settings into map 1 and 2, then I can set all QS cut times in map 2 to zero which will essentially disable the QS. Then I can use the handlebar switch to enable/disable the QS on the fly if the problem comes back.
I know that I do have a technical background and that my job entails electro-mechanical troubleshooting of military equipment... but I'm still a little annoyed that I had to come up with this work-around on my own. I have 5 DNFs at SOAR this season in which I could have scored some good points/hardware/contingency had I been able to disable QS on the fly. Oh well.