Nintendo Switch local split-screen stops working after Minecraft 26.30 update

After updating Minecraft on Nintendo Switch to version 26.30, local split-screen multiplayer no longer works.

Platform:
Nintendo Switch

Game version:
Minecraft Bedrock 26.30

Mode:
Local split-screen on one console, offline/local play

Steps to reproduce:

1. Start Minecraft on Nintendo Switch.

2. Open an existing world with Player 1.

3. Press the button to add a second local player.

4. Select a second Nintendo Switch user profile.

5. The game briefly appears to start split-screen mode.

6. After a moment, the second player is kicked out and the game returns to single-player fullscreen with Player 1 only.

Expected result:
The second local player should join the same world and the game should stay in split-screen mode.

Actual result:
The screen briefly changes as if split-screen is starting, but immediately returns to Player 1 only. No error message appears.

Additional details:

• This started immediately after the latest Minecraft update.

• It happens in different worlds, including an existing survival world and another creative world.

• It also happens when trying with a newly created Nintendo Switch user profile.

• We are not using Microsoft accounts or Nintendo Switch Online.

• We are only trying to play locally on the same console.

• Checking for corrupted data on the Nintendo Switch did not find any problems.

• The game is owned physically on cartridge.