The sky the the Warped Forest biome is rendered bright purple whenever the player is effected with night vision.

To recreate: go to the nether in snapshot 20w06a and find a warped forest.  The effect yourself with night vision (I used the command /effect give @s night vision 1000).

just realized I accidentally created this in the bedrock section so ignore this post.  I am reposting it in the java section.  https://bugs.mojang.com/browse/MC-171550