diff --git a/lib/network.py b/lib/network.py
index e0d26cf80..9e2639872 100644
--- a/lib/network.py
+++ b/lib/network.py
@@ -619,10 +619,11 @@ class Network(util.DaemonThread):
 
     def overload_cb(self, callback):
         def cb2(x):
-            p = x.pop('params')
+            x2 = x.copy()
+            p = x2.pop('params')
             addr = self.h2addr[p[0]]
-            x['params'] = [addr]
-            callback(x)
+            x2['params'] = [addr]
+            callback(x2)
         return cb2
 
     def subscribe_to_addresses(self, addresses, callback):