Can't set difficulty to "Normal" using the Difficulty Adjuster on my island, only "Casual", "Hard", and "Impossible"

[AzyWng]

The issue is exactly what it sounds like. Whenever I try to select "Normal" (or press 2) when using the difficulty adjuster, I get the message saying my difficulty has been set to "casual". Setting the difficulty to "Hard" and "Impossible" seem to both work fine, though (at least, I get the messages saying I've set my difficulty to those settings).

EDIT: I'm currently playing on 2023-08-04-0047