"Make Motion More Natural Using a Bezier Curve" -- does the cubic-bezier function is applied twice? [SOLVED]

HTML-CSS
#1

I finished this challenge and the ball bounce as expected. But, there are two phases of the bouncing, upward and downward. Thus, the ball bounces twice, does the cubic-bezier function is applied twice?

Link to the challenge: https://learn.freecodecamp.org/responsive-web-design/applied-visual-design/make-motion-more-natural-using-a-bezier-curve

#2

I think I’ve figured it out. Every @keyframes frame uses the same animation-timing-function property value. If you want it to be different, you can specify the animation-timing-function within a @keyframes frame rule.

#3