stage3D issue on some android device

Hi ，all

my problem is sample.but the phenomenon is weird.

           stage3D.addEventListener( Event.CONTEXT3D_CREATE, contextCreated );

            stage3D.addEventListener( ErrorEvent.ERROR, contextCreationError );

            stage3D.requestContext3D( Context3DRenderMode.AUTO );

work on some android pad.contextCreated is triggered.

But same program on some other android pad contextCreated and contextCreationError are  both not triggered.

meanwhile  if(stage3D) is true。

Did anyone ever meet this before?? and why