This handy video was right, the motor windings were shorting to the frame through the motor screw. I found that another one of the other motors was shorting too, just not as bad. Interestingly, it was the screw in the same position on both motors. To be safe i took that screw out on the other two motors as well. I had four screws holding in each motor so now i have two in each.

I tested on the bench and the motor definitely doesn't get as hot as it used to, but unfortunately it still gets hotter than the others. The frame doesn't heat up though which is a good sign that nothing is shorting to it. Motor must be damaged or something. I should take the motor off the ESC and beep it out, but for now i'll prob just run it until it dies. It seems to work ok.