A few months ago Firefox began to show the wrong icon for a site I have bookmarked on my toolbar. I have the same site bookmarked in a folder too, but the favicon is correct there. It is only when the site is bookmarked to the toolbar, or the bookmark is copied from where the favicon is correct and pasted to the bookmarks toolbar that the favicon goes wrong. A minor problem to be sure, but odd and I would not mind fixing it. Thanks for any ideas.

I am using FF 81.01 and Windows 10 with most recent updates