--- a/net/minecraft/world/level/block/entity/SculkCatalystBlockEntity.java
+++ b/net/minecraft/world/level/block/entity/SculkCatalystBlockEntity.java
@@ -43,9 +_,9 @@
     // Paper end - Fix NPE in SculkBloomEvent world access
 
     public static void serverTick(Level level, BlockPos pos, BlockState state, SculkCatalystBlockEntity sculkCatalyst) {
-        org.bukkit.craftbukkit.event.CraftEventFactory.sourceBlockOverride = sculkCatalyst.getBlockPos(); // CraftBukkit - SPIGOT-7068: Add source block override, not the most elegant way but better than passing down a BlockPosition up to five methods deep.
+        org.bukkit.craftbukkit.event.CraftEventFactory.sourceBlockOverrideRT.set(sculkCatalyst.getBlockPos()); // CraftBukkit - SPIGOT-7068: Add source block override, not the most elegant way but better than passing down a BlockPosition up to five methods deep. // Folia - region threading
         sculkCatalyst.catalystListener.getSculkSpreader().updateCursors(level, pos, level.getRandom(), true);
-        org.bukkit.craftbukkit.event.CraftEventFactory.sourceBlockOverride = null; // CraftBukkit
+        org.bukkit.craftbukkit.event.CraftEventFactory.sourceBlockOverrideRT.set(null); // CraftBukkit // Folia - region threading
     }
 
     @Override
