User hero is always white

Normally the .UserHero background color is set via inline style by Flarum according to the dominant color of the avatar.

But all our profiles are now white.
Using the latest version of Flarum and extensions

Can you provide a link to a profile ?

It's a private forum, so unfortunately not.
What are you looking for? JS code/console?

edit: console has no error output

fixed: some other admin changed the css of the Hero to a white background. Doh!