It's hard to see these helmet to helmet hits in real time and especially in that situation. The end zone is the primary concern for the officials in this situation. The fact that they didn't see it is not a surprise. It happened at the same time Peters crosses the goal line.
They are in reverse mechanics because of the interception. The white hat would have that call and the line of scrimmage official would have goal line responsibilities (he shouldn't be looking for head contact) but because they are reverse the white hat was probably looking at the goal line, which is a very common mistake.
Someone said Intentional......I doubt it, he is an O lineman, he hasn't been asked to tackle someone very often since he was in HS.
(I think you guys know I officiate HS, JC and semi pro ball)