I remember reading that although the Xg remains the same for penalties, statistically the conversion rate goes down significantly if the team is level or behind, when the penalty is awarded.
I think the proportion of pens scored when the team is already ahead is over 90%
There is also a possibility that it's just an odd stat and nothing to do with Pedro at all.
The keeper guessing the correct side from just 1 in 8 attempts is impressive, but not impossible.
In reality he is currently on a run of 7 without the keeper guessing correctly.
odds of that are...