reveal image strange behaviour

Hi, i replicated this codepen via bricks and then on motion.page:

It works, but in codepen, scrolling the page, after the start point is reached, the reveal animation starts and goes alone regardless of the scroll.

While in motion.page, scrolling the page, after the start point is reached, the animation start but if I don't scroll it stays still at that point, I have to scroll to restart the animation.

The image it opens only if i scroll.

In codepen the image it opens also if i don't scroll.

I would like to do the animation like in the codepen, so that the image it opens also if i don't scroll

How can I do?

I miss something?

Thanks Davide