The Bug

In some cases a beach biome is generated between deserts and oceans. This did not happen in 21w39a.

How to Reporduce

(updated to 21w41a)

Seed: 1
/execute in minecraft:overworld run tp @s 8420.70 81.13 15394.45 -225.30 55.65

Cause
The "pickBeachBiome" function in the BiomeBuilder decides between beach and desert by:

return temperature == 4 && humidity < 3 ? Biomes.DESERT : Biomes.BEACH

Until 21w39a this matched the placement of deserts by "pickMiddleBiome". However in 21w40a deserts are also generated in areas with temperature == 4 and humidity >= 3, but the "pickBeachBiome" function was not updated accordingly.