That doesn't seem right. Does this happen on all videos or particular video? Also, you try deleting the app, restarting your device and reinstalling the app. Let us know if this works.
That's odd, could you file a feedback report with these steps: https://goo.gl/1ckkO5 ? While every individual report may not get a direct response, we do review everything and use the details to investigate and fix issues. Thanks!