I want to share my theory with you.
Jack left the island, somebody killed him, his father made Jack wear those sneakers, Christian brought his son to the island, took the shoes off, threw the snicker away, and the sneaker hung on a branch. And He went far away and sent the Vincent to wake him up.
Jack was chasing his father in the jungle. He came across the coffin. When he opened, he got angry. Why ? Because Jack's second body was not there. Monster took Jack's second body.
I want to give you this example. Let's say 5th season is actually first season. Flocke opens his eyes goes into the jungle. He meets a crate ( which Iliana carries ), opens it. He gets angry because it is empty. And beats it with a stick. Why would Flocke get angry to see the crate is empty ? Because his second body is not in it.
So, when Jack beats the coffin, he did not do it because of his father was not inside it. He did it because his second body had already gotten up and walked to the temple.
Also, when Richard took Benjamin to the temple, I believe that Benjamin was already dead. He brought him there so that the monster could take his body.
I do not have any clue. But when I think this, this is not impossible.