Brushless swap problem

[T-birdJunkie]

So, for years, I've been running brushed in my 2wd buggies. I've been running pretty much nothing but 14x2 motors, and having no issues keeping up even with the 7.5s and 8.5s at the track. Car runs cool, runs fast, and needs a comm cut maybe every 10 to 14 race days with a cleaning here and there and the occasional brush swap. It's been dead nuts reliable.

Until now.

Dropped a Tekin 13.5 into it that I got from a buddy, and as soon as the car was plugged in, it basically went FIZZZZZZZZZZ *smoke*. The motor only had 3 runs on it when it was put into the B4.1 FT in question, and it ran perfect when it was pulled from a buddy's RB5.

Any ideas on what may have happened? Here are before swap and after swap pics. Hopefully you see something I don't.