Video renders black the second time

Scenario:

I am integrating Vuforia screen within my iOS Application and want to play video on the target image overlay. I have used videoplayback sample for my reference. This works fine and the target detection and video is as expected.

I need to perform the following action:

Launch Application -> Click one of the button to launch vuforia scanning module -> Play video on detecting right tecture -> Press button to  navigate to other parts of the application -> Click Button to launch vuforia scanning module again.

Steps Used:

When the user clicks on button we initialize QCAR and all other relevant stuff related to Vuforia and let the target detection happen and video play on texture. On clicking a separate exit button, we uninitialize QCAR and unload everything relevant to vuforia. And perform the same everytime user wants to scan image target.

Problem:

I scan and detect Image A And play corresponding Video A for the first time and it works perfectly fine. However once i unload everything and reinitialize vuforia, the second time the target detection works fine but I only see black screen rendered for the video. 

This seems like a rendering issue, though what beats me why does this happen only second time. Another note, the second time intialization is correct as if I track a separate image then that relevant video plays back perfectly.

Any pointers would be appreciated.