This has been proved again. It is to do with his height and relative build. His tendons have to do more work and are under more strain than in other players, yet they are made of exactly the same biological material. Think of Cam Smith's physical invulnerability by comparison.
As far as I recall he first stuffed his hamstring while skylarking running along the Manly Corso and was out for a couple of months. It happens to him easily, just running on the Corso.
I don't see how in last night's incident his lower legs hitting the cameraman's legs could have damaged his hamstring. I think it happened an instant before trying to make the tackle on the try scorer.
It is a shame because he is a great footballer when on the field, which is never for any sustained period of time.