[Garan]

OK. What is happening is that Turbine has enforced an additional restriction so that Lua can only be aware of what the client would natively be able to display. The Actor.TargetChanged event and Actor:GetTarget() method are only valid if the Actor is either the local player, the target of the local player or a party member that is also a raid target assist.

So, you can see a party member's target and get target changed events if the party member is also a raid target assist since the built-in raid assist window would also display that information but you can not see a non-target assist target unless you are currently targeting the player thus enforcing the same restrictions that the native displays enforce.

FWIW, I don't particularly like this restriction, but now that I see the conditions I can see why Turbine implemented it this way to restrict Lua to only the information that would be available to a player using the built-in interface.