Thank u for u answer. I make same tests. Its work when u receive crit but not always or if u receive crit from melee attacks. Corrosive damage not trigger it. Or mb spell holding effect have any global culdown? In first fight i have proc after crit, but no1 in second. U can see on screen no procs from all sources.
http://i.imgur.com/cQnkrQ6.jpg