[Rahaze]

There was a bug at least a couple patches ago where certain players would be invisible to me. If we were grouped, their health bar had the appearance like they were in the other zone. They could be moving with me, attacking with me, but be completely invisible and possibly untargetable even when I could read their attack damage and share xp with them. No invisibility spells were cast or abilities were used or else they wouldn't have been able to fight with me in that one case where I could see their attack messages.

It's worth noting, they could see my character even though I couldn't see them. One time it happened with a lower level player coming to me for loot in Nektulous. They wondered why I ignored them like they didn't exist as others cut them aline, it's because they didn't exist on my screen until I asked them to try relogging. It happened in Innothule and maybe guk also.

I put off reporting this for a while because I don't know what causes it. A relog by one of the players fixes it, and I think zoning might fix it too but not certain on that. It's pretty jarring when it happens though so I hope it's not just me that noticed. You can still group with characters invisible to you if someone else invites them and being grouped or not has no effect on who will randomly be invisible. They could be watching you.. anywhere. Good luck on there.