The /locatebiome command would usually only give the X and Z coordinates. This is usually fine for most biomes, however, with the new lush and dripstone cave biomes, it should give the Y coordinate, instead of using ~ to teleport you to the new coordinates with your current Y value.

With normal biomes, the /locatebiome command should stay as usual, but with cave biomes, it should provide the Y coordinates. This is because, as of 21w41a, biomes can change over the Y axis if there is a cave biome.

Steps to reproduce:

Use either:

/locatebiome minecraft:dripstone_caves

or 

/locatebiome minecraft:lush_caves

Will return with the X and Z coordinates of the nearest of that biome, but not the Y coordinates. If you click on the returned coordinates, it will also just run the teleport command with no Y coordinates specified as it usually would with a normal biome.