Killed this boss 4 times this morning . My weekly endeavor to "Complete 7 Public Dungeon Group Events still shows zero complete: https://youtu.be/p3tWzTp2Qvs
I recall high isle public dungeons also haven't worked for this achievement in the past. I know Summerset does, so at some point DLC public dungeon group events just stopped being coded the same I guess...
Noticed this last time "Kill a Public Dungeon Group Boss" was a daily endeavor, a week or so ago. I soloed it so there's no chance that it was because I didn't do enough damage.