When using custom biomes, trying to add a configured feature that includes the minecraft:decorated feature found in the most recent vanilla worldgen files provided by slicedlime causes all configured features for that biome to not load.

EXPECTED: Trees and stuff should appear in the world.

ACTUAL: No configured features appear at all.

Attached is an example data pack that the bug appears in. (Note that the configured feature example:example is an exact copy of trees_birch from the vanilla worldgen files, except for the name.) I've also included a picture of the empty world that appears, instead of one full of trees like there should be. 

EDIT: The launcher log returns this error when attempting to use the data pack:

Feature: No key name in MapLike\\{"config":{"feature":"minecraft:birch_bees_0002","decorator":{"config":{"outer":{"config":{},"type":"minecraft:square"},"inner":\\{"config":{},"type":"minecraft:heightmap"}},"type":"minecraft:decorated"}},"type":"minecraft:decorated"}

Complete launcher log: https://paste.ubuntu.com/p/Wm8bC4nXmt/