FWIW, we are seeing the “sketchy” default favicon on our site https://bf1.akimbo.com which is hosted by Discourse with a Business plan.
We have a favicon uploaded in the settings, and it’s displaying properly for logged-out users…
… and for admin/staff users.
But it’s showing the “sketchy default” favicon for logged-in non-admin users.
I’ve just tried changing the “Show new / updated topic count on browser icon” setting to see if that helps.
Any thing else I should try?