I have a strange problem with volume of the some specific(?) videos when using Firefox.
I'm not sure if it's only the Firefox problem because it's happening with the volume slider for the applications in the system tray. Some videos (not only on Youtube but at least on Crunchyroll too) have their max volume set to less then 100% which I CAN change to 100% and it works, but it comes back to the previous value if I manually change the timeline of the video. It happens with some specific videos and I'd assume it's because of some setting that prevents the sound from getting too loud for my ears, but I couldn't find such thing in the system settings and with the Crunchyroll the sound on 100% volume is not even loud on the videos this bug happens to.