Invalid cubic bezier formula

[tmaxmax]

Something I have noticed is that the formula you use for determining the Bezier easing percentage isn't valid.

The formula finds either the horizontal or vertical coordinate of a point on the Cubic Bezier curve. Although it is correct, you are mixing the coordinates, using both coordinates of the control points, instead of only one. This error results in an incorrect completion percentage of the animation.

I would suggest using a separate implementation of the Cubic Bezier easing curves if you wish to keep this feature or use only the timing functions for easing.