Guild Wars 2

So whenever I join a friend in their home instance or their main quest instance, if I summon my own merchant, I cannot interact with my merchant
This seems very strange.
Can this be fixed

Has anyone else had this problem?

Whenever I’ve been in someone else’s instance, I cannot talk to any NPCs. They just ignore me. I feel like a ghost. I imagine that’s what’s happening here. It’s adding your merchant as an NPC and it’s ignoring you because it’s not your instance. I get that the non-owners should not get any controlling interest in the instance, but talking to merchants/NPCs should be allowed, at least.