My second extruder plug occurred when I inadvertently broke my 15 min hot limit. The higher speed printing stripped the orange filament and allowed the filament to remain stationary while the hot end was heated and the heat propagated up the filament past the white thermal isolator and bulged just above it. That bulge will not go down the hole no matter how hard you push now. So here it is disassembled showing where the bulge is at the junction between the extruder body and the thermal isolator. Note the chewed out filament where the pinch wheel stripped it.