problems playing split screen on realm

We are accessing the realm from Nintendo Switch. We have been doing this for a couple of years without issue. Recently, we loaded a new world onto the realm and attempted to play split screen.

When player 2 tries to join the realm, it attempts to load player 2, but loading fails after a few seconds, leaving player one in the realm.

If the second player tries to join the realm by themselves (not the owner), they sometimes load with the owner's skin, inventory, or both. If I download the world and play locally, the world behaves as expected.

In summary, the realm appears unable to resolve Switch player profiles appropriately.