diff --git a/sdk/android/api/org/webrtc/DataChannel.java b/sdk/android/api/org/webrtc/DataChannel.java
index f51dab9..bcbf6f0 100644
--- a/sdk/android/api/org/webrtc/DataChannel.java
+++ b/sdk/android/api/org/webrtc/DataChannel.java
@@ -123,6 +123,7 @@
   public void unregisterObserver() {
     checkDataChannelExists();
     nativeUnregisterObserver(nativeObserver);
+    nativeObserver = 0;
   }
 
   public String label() {