No idea if there was an update to the shop. I just know there was only a couple mp pots, but when I bought them they always had more.
Also encountered a couple bugs, not sure if it's from restarting so much, or running away from the Arena.
One was after I escaped from mobs I did 0s to, while I was going through other menus all of a sudden an empty battle popped up. Moving caused the game to give me a win to the heroic arena I was in before escaping.
Another one, was the mobs hp were around 1/3 of it's original value. It didn't fix itself until I won an arena.