I noticed a glitch where if you move from a biome the doesn't rain like mesa and desert to a cave biome that rains (in my case it's dripstone_caves), it can rain there but if you start fly up and out the cave where you enter a biome that doesn't rain, it will stop raining when it's supposed to rain down the cave biome that can rain. Mojang needs to improve their new 3D biome and let them match some properties of the biome above and below them.

(Video attached is super compressed)