diff --git a/owlps-positioner/mobile.cc b/owlps-positioner/mobile.cc
index b03cd82..fec9c11 100644
--- a/owlps-positioner/mobile.cc
+++ b/owlps-positioner/mobile.cc
@@ -67,6 +67,10 @@ Mobile& Mobile::operator=(const Mobile &m)
 
   this->WifiDevice::operator=(m) ;
 
+  last_request = nullptr;
+  last_results = m.last_results;
+  update_last_request();
+
   return *this ;
 }
 
@@ -76,6 +80,9 @@ bool Mobile::operator==(const Mobile &m) const
   if (this == &m)
     return true ;
 
+  if (last_results != m.last_results)
+    return false;
+
   return
     this->WifiDevice::operator==(m) ;
 }