Not seeing any flares from plain 0x runestaff with 411. I see plenty of flares with every other flaring runestaff I try.

Chad, player of a few

If the damage from the blow, OR the crit resulting from damage, results in the death of the target, I believe that you will not get a flare on that swing. For the longest while, my ambushing Thief was firmly convinced that certain weapons just didn't flare, simply because he never saw one.