I definitely have seen Sneak Attack trigger on AoOs, but I can believe that's only when my character hasn't already used their Sneak Attack that round.
I just did a sneak attack on my turn and then a sneak attack the very next creature's turn on an AoO.
Interesting to know! I still haven't seen that, but then my character is usually at range.
Odd instance where Astarian and another character both started combat in melee range of the enemy (the Gul monster hunter). Astarian did a melee sneak attack on him and then on his turn the Gul moved away, provoking AoO and I got the prompt to apply sneak attack agian.
