I’m not quite sure, but I can make some guesses.
Some animals, especially those that live in trees have a natural grasping reflex to grab onto branches or stems, so it may have just come across the leaf whilst leaping along and its foot came to grasp it, maybe picking it up, or breaking it away when it leaped again.
A more far fetched theory could be, that it looks like there is some water collected in the leaf, and rainforest frogs are known to lay their spawn in puddles collecting on leaves or in hollow tree stumps. They usually carry the tadpoles on their backs when the water starts to dry out to take them to a place with more water and food sources, so the leaf may contain its offspring, or water to add to the puddle they are in. Although I think that is a little more imaginative.