The bug
The "Desert Lakes" biome no longer generates as of the 1.18 snapshots.
A multitude of biomes were removed from generation in 1.18's development due to being trivial height differences for handling more or less mountainious regions in a given world. Mushroom Fields Shore (MC-236653) is an example of such a deprecated biome. With 1.18 splitting hilliness off from biomes, they are no longer needed, and as such no longer generate.
Source: https://www.youtube.com/watch?v=6Ffu1gTEsVo&t=2m12s
However, there are many other biome variants which made other changes rather than just making the place more hilly, such as sunflower plains and flower forests, which ultimately were kept in. Desert Lakes, however, does not seem to be present anymore, despite it having differences beyond hilliness differences.
Expected behaviour
Desert Lakes biomes would still generate in worlds, since they have water lake features in them, differentiating them from normal deserts in a way that isn't just basic terrain based.
Actual behaviour
The biome does not seem to generate at all.
[media][media]
How to reproduce
/locatebiome minecraft:desert_lakes
Can confirm, but might be intended as they removed water lake features from generating on hot biomes.