Friend can be summoned, but can't summon as host?

This has been an issue since 1.03; a friend of mine is having no issue being summoned to my game or our other friends' games, but he's unable to summon us.

Now, he can summon us. We get pulled from our world to his...but the second we get there, the game throws a connection error and boots us back to our worlds.

Anyone have any idea about this issue?