Swampland biome not correctly amplified

The swampland biome is not correctly generated if the world generation is "AMPLIFIED"

Step 1: Clic on "create new world".
Step 2: Set the gamemode to creative.
Step 3: Clic on "More world option...".
Step 4: Set the World Type to "AMPLIFIED".
Step 5: Enter this seed by example: -379748870562298331
Step 6: Clic on "Create new world".
Step 7: Open the chat.
Step 8: Type "/tp 70 65 700".
Step 9: Look this mysterious bug.