Bug 464577

SUMMARY
While watching YouTube music videos in Firefox, the audio volume level in the Audio Volume System Tray Applet changes to random values when a new video starts.


STEPS TO REPRODUCE
1. Open Firefox.
2. Visit YouTube.
3. Start playing a music video.
4. Open the Audio Volume System Tray Icon (Applet? Plasmoid? Widget? - Not sure of the actual name of this thing).
5. Click on the Applications Tab.
6. Click on the Keep Open/Pin Button (the thumbtack/pushpin icon in the top right corner of the applet window) so the Audio Volume Applet stays open.
7. Click the next video button on the YouTube Video Player and let the video play for a few seconds.
8. Observe the volume level percentage.
9. Repeat steps 7 & 8 several times and notice the volume level percentage changes to a different random value almost every time you skip to the next video or the video changes on its own.


OBSERVED RESULT
When watching music videos on YouTube in Firefox, the volume level percentage changes to a different random volume level percentage on almost every change/skip to the next video and the change is visible in the Audio Volume System Tray Applet and also the change is auditorially (Actually hearing the music through your computer speakers with your ears) noticeable when 1 music video is playing and you manually increase the volume level percentage slider up to 100% in the Audio Volume System Tray Applet and then either skip to the next video or let the existing video finish playing and auto play the next video (when the next video starts, visually notice the change in the volume level percentage and also notice the difference in audio volume level by listening with your ears.)

EXPECTED RESULT
The audio volume level does not change at all and remains at what it was set to before. (Playing music videos on YouTube should not affect the volume level.)

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: KDE Neon Testing Edition (ISO Dated: Jan. 19th, 2023)
(available in About System)
KDE Plasma Version: 5.26.90
KDE Frameworks Version: 5.102.0
Qt Version: 5.15.8

ADDITIONAL INFORMATION
This problem also occurs on my KDE Arch Linux installation (KDE Plasma 5.26.5 Stable - KDE Frameworks 5.102 - Qt 5.15.8) on my computer. I don't believe this problem is Linux Distro specific.

The YouTube Video Player's volume never changes and is always at 100% by default.