[One X9] Glitches while watching YouTube, why?

[AC Question]

Hello everyone
Whenever i watch youtube on phone whether it is by app or on browser the video freezes and a small screen appears at the top left corner where the video would be playing. Why is this happening? Is it because of youtube issues or is there something wrong with my phones display?? I use an htc one x9

 

[B. Diddy]

Welcome to Android Central! Does this happen on both wi-fi and mobile data? How about other streaming video sites or apps?