Youtube lowering resolution on unwatched tab
I'm running the desktop version of FF 132.0 with no adblockers.
When watching a YT video at 1080p, if I leave the tab to look at other tabs, when I go back to the video playing it's dropped the resolution to 640*360. It is annoying because I don't know if YT or FF is adjusting the resolution.
If have two instances of FF open with YT running in one tab only (on a single tab with no other tabs open), the I browse using the second instance of FF. The video still lowers in resolution, when I'm not actively watching.
Is it FF, YT or perhaps my GPU trying to save bandwidth?
My PC specs are 5900x, 32GB DDR4, rx7700xt running Windows 11.