In the previous issue I reported, I and some few others (I was the duplicate) said that Mojang needs to fix that the lukewarm and warm ocean not generating very much in game, now they fixed the lukewarm ocean (even thought they said our issues worked as intended) in the version 18w16a.
As of the fix of this, the warm ocean is still not yet in! I've used a biome finder mod in Minecraft to try finding the biome but I didn't find any warm ocean in the nearest 5000 block in about 5 seeds. This makes finding coral very hard as coral only generates in FEW warm oceans.
This isn't a duplicate as I am typing this. Some may be similar. Thanks 😃
It works fine for me. As the devs have said, the warm ocean biomes will only generate within the lukewarm ocean biomes, but the warm oceans do not generate in every lukewarm ocean biome. In my experience they generate uncommonly, but definitely not how you described it. Considering that mushroom biomes are much rarer than warm oceans (and even icebergs), I think the rate that uncommon ocean types generate is intended and just fine.