update mappings and 21w40a, apparently.

src/main/java/carpet/script/api/WorldAccess.java

@@ -1187,7 +1187,7 @@ public class WorldAccess {
                 int j = i + BiomeCoords.fromBlock(chunk.getHeight()) - 1;
                 int k = MathHelper.clamp(biomeY, i, j);
                 int l = chunk.getSectionIndex(BiomeCoords.toBlock(k));
-                chunk.getSection(l).method_38294().setSync(biomeX & 3, k & 3, biomeZ & 3, biome);
+                chunk.getSection(l).method_38294().set(biomeX & 3, k & 3, biomeZ & 3, biome);
             } catch (Throwable var8) {
                 return Value.FALSE;
             }