I discovered an interesting bug with arrow of many targets:

I am playong in honor mode. I have 3 characters with gear that states that you can'r receive critical hits: The helm from the grym on one character, the adamantine armor on another, and the adamantine shield on the 3rd character. At the end of Act II, a githyanki landed a critical hit with an arrow of many targets on the one character without this gear, and proceeded to land a critical hit ON MY ENTIRE PARTY! Luckily I survived, but it appears this is an exception to that rule or a bug.