diff --git a/modules/RTC/TraceablePeerConnection.js b/modules/RTC/TraceablePeerConnection.js
index 4cf674e1c8..d331e3aecb 100644
--- a/modules/RTC/TraceablePeerConnection.js
+++ b/modules/RTC/TraceablePeerConnection.js
@@ -2324,6 +2324,8 @@ TraceablePeerConnection.prototype._updateVideoSenderEncodings = function(frameHe
             // Configure scalability mode when its supported and enabled.
             if (scalabilityModes) {
                 parameters.encodings[encoding].scalabilityMode = scalabilityModes[encoding];
+            } else {
+                parameters.encodings[encoding].scalabilityMode = undefined;
             }
         }
     }