Theory on the Ending (SPOILERS)
I think that the end shows that Chance, like the Road Runner (who also defies gravity), he will not sink until he understands his dilemma.
It makes sense in the context of the film.
Thoughts?
I agree.
It's not like he was some mystical, magical guy.
This was his very first interaction with a body of water and therefore he did not know he was supposed to sink which is why he walked on it.