I thought it was a fairly obvious pen myself, not cast iron but one you’d expect to be given. It travelled a long way before it hit his arm, it’s not like it was a mad ricochet he couldn’t avoid.
I saw Sutton's take that it's an outrage and it's not that.
It's one of them that according to the laws, I can't see how it's a pen as his arm is not in an unnatural position, and he's not making himself bigger.
But the eye test would be it probably is. It looks very odd. For what it's worth I think it looks odd because he's trying to block a fairly tame, deflected shot from which is a stupid thing to do, not necessarily because I think he's trying g to handball it.
I'm not sure VAR should overturn, as it's not a huge clanger (either way). I'm disappointed the ref gave it, because he clearly cant see and I can't see how the linesman can see either. But unless the ref has specifically asked VAR "is his arm in an unnatural position/making himself bigger" I cant see how they can overturn it.
I can also sort of see why a common sense view would be if you jump towards making a block of a shot from 15 yards away and it hits your arm that would be a foul though.