YACL serialises config with FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES
(and serializeNulls), so the camelCase keys biomeSpec, leafInsect, seaBunny,
stagBeetle, rolyPoly and stickBug were never read. Every SpawnEntry then
deserialised with biomeSpec = null, and CAC 2.7.0's SpawnEntry.isTag() calls
biomeSpec.startsWith("#") without a null check, crashing FMLCommonSetup on
both the dedicated server and the client.
Rename the keys; all tuned weights and biome specs are unchanged. Missing
keys still fall back to mod defaults (partial file). Refresh the index and
pack hashes.
logan
8e8483d072