This is my first post and I specifically registered here for this issue as it was driving me insane in my first playthrough.
I played COOP, Main Singlehanded with shield pure Man-at-Arms, Madorra pure Man-ar-Arms with two-handed, my buddy went lone-wolf glass-cannon mage (not that it matters for this issue, just to give you an overview).
What I noticed is that even when my main-character or Madorra stood surrounded by 4 enemies with a displayed chance to hit of 100% (was higher, if not internally capped thanks to precision stance and blessing), Flurry would miss 1 out of the 4 hits almost always. Also Whirlwind and Dust-Devil where almost certain to miss at least one of the 4 enemies (remember: all of them had a displayed hit-chance of 100%).
Now, granted, I'm only an IT-guy and therefore not extremly high skilled in math, but so far I took a 100% chance to do anything for granted my whole life ^^
tldr: Not even a displayed chance to hit of 100% is really 100% chance to hit.
