This seems to only affect mash-up/resource packs from the store. Whenever a friend tries to join my world when I have “require players to install resource pack when joining” ticked, they will install the entire pack but fail to connect due to the pack not properly equipping. If I don’t have that box ticked they can join no problem but they of course don’t have the resource pack. This has happened with both the “Natural resource pack” and the “Fallout Mash-up Pack.” If a player has the pack I’m using already bought and installed, there is no problems.

This problem seems to only exist on marketplace content. I joined a friends world who had a custom resource pack, not from the store, and the pack downloaded and installed no problem. My resource packs are up to date. And so is my game. I’ve had people from Windows 10, iOS and Xbox One try to join and every single one of the had the same issue.