QML Video element becomes transparent after key lock/unlock

Application with qml containing Video element becomes transparent after key locking and then unlocking. Whole area which is filled with qml video element is transparent. If application was launched from menu then menu will be seen through the application(i.e. previous screen will be seen)
Attached test application could be used to reproduce the issue.

Devices: Nokia N8, Nokia E7. QML imports: QtMultimediaKit 1.1

Preconditions:
Place any mp4 video to e:\test.mp4

Steps to reproduce:

• Run application and press play;
• Wait when video playback ends(or slide to the end of the video);
• Wait when key lock activates(or lock it manually);
• Press on device menu button and tap on 'Unlock' button

Expected:
Last frame of the video is displayed(or anything else like black background, etc.)
Actual:
Area of the video element becomes transparent

Sometimes it is not reproducible from the 1st time - it is needed to lock/unlock screen several times.