Lots of different problems with intermittent startup, etc. 

looks like the regulator on one of the intermittent ones is messed up 

behaves weirdly

sometimes outputs 12 or 8 volts out of 3v pin 

tried one of the boards pre soldering and works fine

my guess is the bigger header pins required more heat time, plus smaller regulator which is right next to the pins, the regulator was exposed to too much heat and got burned to some extent during soldering (twice)