I've had 3 HHH announcements and then spawns, and sometimes I even see him outlined in purple and hit him once or twice before he leaves, but he keeps running away and despawning, and I don't think he even hits me first.

Update: At 4 now, I'd post screenshots but the best I could get was a boss bar while I was underground mining out a place for a quarry, and a field of monsters above when I made it up there, with no HHH visible.

Update: I got another spawn, it was close enough that I got to charge at him in time, and then when he gave me the "it" effect, I figured out what might be happening, a monster got close to him before I did and got tagged, which he then went off to go chase instead of me. Is there any way the first "it" effect can be made to only apply to a player so if somebody like me is late, they have a chance to fight him?