h.264ify causing problems with playing videos on youtube in latest firefox nightly

[Shaurya-Kalia]

In nightly 98a1 builds dated 27/01/2022 and later, enabling h.264ify is causing problems playing (not loading) videos on youtube.com . The video fails to play, until the page or frame is reloaded. When the video is playing, seeking forward or back will stop video from playing unless the page is reloaded again. Screenshot attached showing the video unable to be played