also having this issue. about 95% of all my deaths while leveling were annoyingly caused by this issue

Not so sure that the boss itself is bugged. From my experience with him, he focuses a person and chases them for a while, randomly switching targets. I've never seen him straight up kill someone from catching them, unless they had low health to begin with. A more prominent problem with operations, however, is that you are unable to zone in after wiping on a boss. The instance says that an encounter is still in progress, even when all the group members have died and are waiting outside the entrance. The only way to fix this is to reset the instance, and re-clear the trash to a boss just to get another attempt. Insanely broken, and very annoying.