Ezren (in a party with Harsk and Kyra) met Kaven Windstrike on Heroic, failed the ridiculous Charisma check (had Darkest Night wildcard as well), got dealt 3 damage which he avoided with a Sihedron Medallion. The Sihedron Medallion then had a recharge check of 11 instead of the usual 9, which I assume is because Kaven's ability to raise the difficulty to defeat when alone by 2 mistakenly triggered on that as well.

So the difficulty is still bleeding. It was Also common bug in 1.02 with some willains like Justing Ironbear.