Previously, the Pit Master axe MI used to convert pierce to physical, but ever since it was changed to instead offer a bleed bonus, the affix weighting wasn’t adjusted to match. It still most often offers Superior or other physical damage based affixes than anything else.
This makes it pretty difficult to get axes that have appropriate affixes, which hurts even more considering how rarely he spawns.
edit: I was told to attach the following screenshot of all the superior axes I’ve gotten in a row:
