I can't correct a website Bookmark/Favorite icon on iOS. (It seems like there are stale cache files of some sort on the iPhone that just refuse to be removed. Looking at Safari
in Storage Management there continues to be 3.3MB of data after all of my attempts to clean up. Possible that it could just be the database structure that take up that space.)
I turned off iCloud for Safari on my devices.
I deleted all bookmarks and reset Safari on my mac.
Removed Favicon Cache and Touch Icons Cache on mac.
Cleared Cache and history on my iPhone twice.
Removed all bookmarks and favorites from my iPhone.
Reinstalled BigSur over my BigSur installation.
The website in question is https://www.teamunify.com
which hosts managed websites using the same base URL:
https://www.teamunify.com/team/ilpac/page/home
https://www.teamunify.com/team/iscats/page/home
https://www.teamunify.com/Home.jsp?_tabid_=0&team=ilslsc
https://www.teamunify.com/team/isnasa/page/home
https://www.teamunify.com/team/ilhpac/page/home
Whenever I save any of these sites as bookmarks on iOS they all use the Bookmark/Favorite icon of one site only: https://www.teamunify.com/team/ilhpac/page/home