Looking for some help / possible bug.

Our group is currently pushing into Eternal. Our Meiko tank is having some issues occasionally where he will go through a combo sequence only to have his finisher greyed out and unable to use it. The issue seems to have popped up in the last week or so.

As far as I know it only happens on the finisher / final hit. He’s in melee range. Can clearly reach the mob.

He cannot reproduce it on the training dummies in the stronghold. It’s only in dungeons.

Has anyone else experienced this?