This is caused by a change in Strobe Media Playback which exposed the setter on autoDynamicStreamSwitch to the JavaScript API.
When fixing the bug I discovered and had to implement an workaround for:
http://bugs.adobe.com/jira/browse/FM-1172 - Setting autoDynamicStreamSwitch on MediaPlayer does not propagate this value to the DynamicStreamingTrait yet for onIsDynamicStreamChange event handler
