Split-screen: player 2 joining a new world kicks back to world list; pre-26.40 worlds work

When a second local player joins split-screen in any world created on a recent version, the game briefly shows split-screen, then exits the world and returns to the world selection screen. Worlds created earlier in 2026 (before the 26.40/26.50 updates) still work in split-screen on the same console and game version.

Steps to Reproduce:

1. Create a new world with default settings

2. Load the world as player 1

3. Press + on a second controller to join as player 2

Observed Results:
Split-screen appears for about a second, then the game leaves the world and returns to the world selection screen. No error message is shown, and the application does not close.

Expected Results:
Split-screen starts and both players can play in the world.

Reproducibility:
Every newly created world, including one created immediately before testing. Not reproducible in worlds created earlier in 2026 on the original Nintendo Switch.

Timeline:
Started in August-September 2026 on the Nintendo Switch version (running on Switch 2), after the 26.40/26.50 updates. Still present in the native Nintendo Switch 2 version (26.60) on system version 23.0.1.

Possible cause:
26.40 and 26.50 introduced behavior gated on a world's base game version (e.g., stair corner and thin-fence/trip-wire connection-state neighbor updates that apply only to worlds created on 1.26.40/1.26.50+). This matches the old-world/new-world split. This is a guess, not confirmed.

Troubleshooting already tried, none of which fixed it:

• Reinstalled the game directly onto the console's internal storage

• Fully uninstalled and reinstalled the game

• Cleared all game cache

• Removed all other games from the console

• Restarted the console

• Lowered or turned off all graphics settings

Workaround:
Split-screen works in worlds created before 26.40.