Bit of a wonky bug, however it seems block proc success for Monk stances were not taking into account your stance correctly. For the most part you were simply granted the default chance (roughly 15% chance).

I've fixed this, but since the class was usually successful to begin with, I'm just going to give a heads up that I'll be keeping an eye on it and likely making some adjustments.

Penned by my hand on Closday, the 25th of Ios, in the year 482 MA.