YouTube Player automatically resizing

[kshitij1210]

My YouTube player is automatically resizing. I don't know why it is happening. It's only happening in my account. In my friend's account the video is appearing of default size. I am not using any extension that does this. Also when i do inspect element something like flexy_at_all_sizes is appearing in ytd player in mine which is not there in my friend's account. Also when I sign out this issue is fixed. I can't understand why only my account is affected. Please suggest a fix.
My account pictures -


Pic when I sign out -