Edmonton Oilers' inability to draw penalties is as puzzling as it is persistent

Game Day 23: Oilers at Sabres
The first measure of special teams efficiency in the NHL is done by percentages. What is the conversion rate of the powerplay? What is the success rate of the penalty kill? Add the two together and if the combined percentages are north of 100, that’s pretty solid.
Or it would be, on the dangerous assumption that the number of opportunities are roughly equal for both units. But that has not been the case for the Edmonton Oilers this season, and especially this