Samsung S4 - YouTube 60fps doesn't work fullscreen?

[AC Question]

I own a Samsung Galaxy s4 GT-i9505 (android v. 5.0.1.). For some odd reason, the video will play at 30fps instead of 60 in fullscreen mode, even though the option is available and checked (720p60fps, it can go up to 1080p only if the video is at 30fps). It only works in vertical position in a small window.
Is my phone that limited or is it a software issue? Any helpful tips are greatly appreciated.

 

[mehigh101]

Welcome to Android Central!
Well if it can show a small portion at 60 f/s it will show the whole screen at 60f/s.
I think you should clear Youtube's app data
Best regards,Mikey. I hope you found what you were looking for.
Sent from my Samsung Galaxy S7 Edge SM-G935F.

 

[LiS420]

It still persists sadly. Although I can tell that there is a slight difference, it's still far from 60fps.