The glow effect from eating rainbow jellyfish disappears on entering the volcano (the character doesn't emit light anymore). If you leave the volcano, the glow returns.
Steps to Reproduce
1. Eat rainbow jellyfish to emit light 2. Enter the volcano 3. You are now in the volcano biome and the character doesn't emit light anymore 4. Leave the volcano 5. You are now in the ocean and the character emits light again (Nintendo Switch)
This issue has not been confirmed by a developer yet.