As for what happened: the nub is missing!!! I have some idea how it happened but am not certain. I unloaded my bike from my truck after returning from my track day two weeks ago and haven't looked at it until I was in my garage last night.
The nub on the lever is just gone. I had a close call at Streets in one of the later sessions where I leaned into a left turn and caught the gear shift on the pavement. It was hard enough to knock me out of gear. When that happened, I swerved right, left and right before regaining composure. I suspect I must have gone so far right that it broke the lever.