They watched a leaf that does not stop moving even though there was no wind. This is different from other leaves that only move when there was a breeze that touches the leaves. The leaf could also be held for a while, but after being released, the leaf is moving back to normal (moving on without stopping).
Although no direct research on this incident but based on modern science, it can certainly be a normal phenomenon just like the theory of aero dynamics. A Muslim may claim that it is (a moving leaf) is one of power and miracles of God, but only within reasonable limits as a form of self-introspection of obedience to Allah. Do not let this incident make calamity by making the leaf as offerings or by performing special worship and prayer around the leaf.
A Muslim must make natural phenomena like that to further examine the science to support, develop, and improve the technology without leaving obedience to God.