Markind,

Did your swashplate move only left and right before you added the mix or did it tilt a little front and back?

The stock Axe only tilts the swash left or right with the two servos on the left and right. With front and back cyclic, all 3 would move, the front going up and the two rears going down for example.

Perhaps the mixing of left/right was not balanced causing one to go up more than one would go down and viceversa. Adding mix will fix it, but its fixing a sympton not the cause.