Flash Player seems to remove some URLRequest parameters by name

Hi

We suddently started having some problems with our video player.

We use the URLRequest.data

The code is pretty much taken from the example.

Now theres one particular parameter named "videoFile" and this just disappears in firefox but works fine in chrome and IE11.

If I rename the parameter to "video" then it works. If I rename it to "videoUrl" then it also disappears.. Very strange..

Even more strange it works if I install the debug flash player of the same version ..

code example

So in the below code the url when inspected in the debug tools network tab will show the parameters "exampleSessionId" and "exampleUserLabel" but "videoFile" is somehow gone.

public function URLVariablesExample() {

    var url:String = "http://www.[yourDomain].com/application.jsp";

    var request:URLRequest = new URLRequest(url);

    var variables:URLVariables = new URLVariables();

    variables.exampleSessionId = new Date().getTime();

    variables.exampleUserLabel = "guest";

    variables.videoFile = "intro.flv";

    request.data = variables;

    navigateToURL(request);

  }

Problem occurs on:

Windows 7 and 8.1 at least

Firefox 46.0.1

Flash player 21.0.0.213 (but works in 21.0.0.213 debug version)