Im using an Ipad, downloaded fsecure SAFE from app store, browser working properly fine but not videos on youtube and including your tutorial videos. I can only hear the audio but video is frozen.
Sorry for my reply.
While there missing any other replies yet.
But does it possible that trouble not really based on F-Secure SAFE?
At least, I just tried search Google with query "iOS youtube audio, but not video" and some of first URLs about such trouble, which sounds like your (include that there "iPad") - where briefly not visible about reasons (youtube, iOS or certain settings under browser);
If you still experienced with such trouble - maybe you able try contact direct F-Secure Support Channels. Like chat ( https://www.f-secure.com/en/web/home_global/support/contact-chat ) or phone ( https://www.f-secure.com/en/web/home_global/support/contact-support );
Sorry else one time.