I have now heard a couple different versions of what happened.
According to DiMuro, the ball skipped off the top of the wall and hit concrete beyond the wall and bounced back.
According to another media outlet, the official ruling from MLB was that since the ball hit above the padding, it was a HR. It didn't matter that it didn't clear the wall, just that it cleared the padding on the wall.
To both of these, I have to say WOW!!!
According to said media outlet, MLB has corrected this ground rule and now a ball must clear the fence to be a HR. (
you think)