diff --git a/lib/session/call-session.js b/lib/session/call-session.js
index 4bf151f9..5d087f72 100644
--- a/lib/session/call-session.js
+++ b/lib/session/call-session.js
@@ -48,6 +48,7 @@ class CallSession extends Emitter {
     this.taskIdx = 0;
     this.stackIdx = 0;
     this.callGone = false;
+    this.notifiedComplete = false;
 
     this.tmpFiles = new Set();
 
@@ -988,6 +989,12 @@ class CallSession extends Emitter {
   _notifyCallStatusChange({callStatus, sipStatus, duration}) {
     if (this.callMoved) return;
 
+    /* race condition: we hang up at the same time as the caller */
+    if (callStatus === CallStatus.Completed) {
+      if (this.notifiedComplete) return;
+      this.notifiedComplete = true;
+    }
+
     assert((typeof duration === 'number' && callStatus === CallStatus.Completed) ||
       (!duration && callStatus !== CallStatus.Completed),
     'duration MUST be supplied when call completed AND ONLY when call completed');