I definitely did NOT enable MBT pool markers. I don't have the slightest idea what they are. I don't use audiosnap except for control+click stretching clips.

Okay, so what must have happened is a neutrino that left Alpha Centauri A back in 2011 just got here two days ago, crashed into your RAM, coming to rest in the first bit of the register for the 'ShowMBTPool' flag where SONAR mistook it for a 1, and enabled the MBT pool markers.
 

 
 

Clearly.