I made a bookmark on the bookmark bar. The icon showed up. Then a little while later, the icon is gone but the bookmark is still there. Just no icon. Not all icons disappeared off the bookmark bar, just a few, but more than one. I can’t see a pattern. Then another day I believe the icon was back, now it’s gone again. Good grief charlie Brown.
Can’t you cache the icons or something? Are you asking it to fetch the icon every time? Even if you are, I highly doubt youtube removed their favicon.ico file. In fact, it’s right there https://www.youtube.com/favicon.ico