Paper/nms-patches/BlockFluids.patch

--- a/net/minecraft/server/BlockFluids.java
+++ b/net/minecraft/server/BlockFluids.java
@@ -175,14 +175,20 @@
                 Integer integer = (Integer) iblockdata.get(BlockFluids.LEVEL);
 
                 if (integer.intValue() == 0) {
-                    world.setTypeUpdate(blockposition, Blocks.OBSIDIAN.getBlockData());
-                    this.fizz(world, blockposition);
+                    // CraftBukkit start
+                    if (org.bukkit.craftbukkit.event.CraftEventFactory.handleBlockFormEvent(world, blockposition, Blocks.OBSIDIAN.getBlockData(), null)) {
+                        this.fizz(world, blockposition);
+                    }
+                    // CraftBukkit end
                     return true;
                 }
 
                 if (integer.intValue() <= 4) {
-                    world.setTypeUpdate(blockposition, Blocks.COBBLESTONE.getBlockData());
-                    this.fizz(world, blockposition);
+                    // CraftBukkit start
+                    if (org.bukkit.craftbukkit.event.CraftEventFactory.handleBlockFormEvent(world, blockposition, Blocks.COBBLESTONE.getBlockData(), null)) {
+                        this.fizz(world, blockposition);
+                    }
+                    // CraftBukkit end
                     return true;
                 }
             }