World won't allow local specific second player to join with PSN account

First time I've been on since the Nether update and following updates. Latest PS4 firmware and Minecraft version as of 2020-07-24.

 The game appears to not be able to allow a specific local player to load into a specific map (Map A). For context:

• Game / Map A is in my Playstation user's account on the PS4.

• Second player joins via signing into PS4 with their PSN account (stored locally on the PS4) and hitting `Options` as per usual.

• Historically this has been fine. Second player plays regularly with me (we don't actually play separately)

New behaviour:

• My local player loads fine.

• Second player joining Map A locally as above results in game hanging at `Building Terrain` screen

• My player continues to play fine.

• Their avatar renders in the world but cannot be hit and mobs ignore them. They're listed in the currently playing screen.

Things we've tried:

• Using the second controller signed in as "Guest" on the PS4 works on the Map A The game renders fine and the second player can join. Only this person's PSN account seems to be affected.

• When using their PSN account the second player may join other worlds including one existing before the recent updates. It is only Map A that appears to be affected.

• We thought it might be something in their inventory causing a bug so we enabled cheats and my user attempted to use the `/clear` and `/kill` commands but received an error message stating the target was not on the map despite being listed in the pause menu.

• Sleeping in a bed doesn't work. My avatar interacts with the bed fine but the time skip doesn't occur, indicating that the other account is required to sleep as well.

• Uninstalling / reinstalling the game.

I've searched online and it appears to be different to the recent Mojang Screen bug. Is this bug already registered and is there a workaround? Otherwise happy to wait it out if Mojang know about this and are planning a fix.