Paper/nms-patches/ChunkTaskDecorate.patch

--- a/net/minecraft/server/ChunkTaskDecorate.java
+++ b/net/minecraft/server/ChunkTaskDecorate.java
@@ -9,6 +9,7 @@
         ProtoChunk protochunk = aprotochunk[aprotochunk.length / 2];
 
         protochunk.a(ChunkStatus.DECORATED);
+        protochunk.needsDecoration = true; // CraftBukkit
         return protochunk;
     }
 }