One motor needs to be reversed due to it facing the opposite direction to the other- hence why the stock erevo (brushed) has one special reversed titan motor (wiggle your fingers in the air and pretend they are motors and the spur, you'll soon see...).
you said random flashing, what you mean?
red, green, red, green, red, green, red, green? mine did that, and it fried :/
just ditch the dual vxl and get a MMM if you can, dual vxl killed my both escs and i ruined one motor
Here's a simple sollution.....Take both velineon systems out......sell them on ebay, prolly get about $125 or so each (just an estimate), buy a MMM combo and be done!