Do you have a screenshot of error message that was displayed by any chance? It seems highly unlikely that only one player would be removed from a duty in progress due to "server full" but not the rest of the party.

Definitely players who are going AFK in solo instances are getting kicked but there's nothing unusual about that.

Quote Originally Posted by Myrany View Post
I am betting the island sanctuaries are running on the same instance servers as dungeons/trials/raids etc. I think I saw they were having problems with that the day of release.
They seem to be hosted on the housing servers. I haven't heard anyone complain about not being able to enter a duty instance but a lot of players are having trouble entering housing and Island Sanctuary instances.