diff --git a/src/pocketmine/level/format/anvil/Chunk.php b/src/pocketmine/level/format/anvil/Chunk.php
index d3491c0c0..c9bd003e7 100644
--- a/src/pocketmine/level/format/anvil/Chunk.php
+++ b/src/pocketmine/level/format/anvil/Chunk.php
@@ -152,7 +152,7 @@ class Chunk extends BaseChunk{
 	}
 
 	public function toBinary(){
-		$nbt = $this->getNBT();
+		$nbt = clone $this->getNBT();
 
 		$nbt->xPos = new Int("xPos", $this->x);
 		$nbt->zPos = new Int("zPos", $this->z);
diff --git a/src/pocketmine/level/format/mcregion/Chunk.php b/src/pocketmine/level/format/mcregion/Chunk.php
index c3b99a86b..0463ac361 100644
--- a/src/pocketmine/level/format/mcregion/Chunk.php
+++ b/src/pocketmine/level/format/mcregion/Chunk.php
@@ -248,7 +248,7 @@ class Chunk extends BaseFullChunk{
 	}
 
 	public function toBinary(){
-		$nbt = $this->getNBT();
+		$nbt = clone $this->getNBT();
 
 		$nbt->xPos = new Int("xPos", $this->x);
 		$nbt->zPos = new Int("zPos", $this->z);