Instanced content
There are some instanced content which is accessible thought portals with party created before port happens. In these instances, you mostly complete some lore quests with possible boss at end or some sort of rare material or part.
Instanced content is locked by weekly limit, to prevent abusive mechanic.
There Are also some instanced dungeons which spawns randomly at world and they are randomly generated inside. These adds some replayability to players. In these dungeson you can farm, complete quests or find RB to fight.. These dungeons stands for 1 week (every restart is there rotation)