Logo and favicon disappeared after upgrade to 3.1.11

Have you copied customizr/parts/class-header-header_main.php in your child-theme dir?

Yep, I did…

That’s wrong, you copied a core file in your child theme. This means that the child-theme file will override the customizr core file. So you will have problems like that, ’cause some other customizr core file will expect something to work according to the new changes but that old file you have in child-theme make things in the old way.
Hope this is understandable ?? (sorry for my english).
The better way to extend/change customizr behavior is to use the large amount of hooks it provides. But if you still want to use your method, at every customizr update you have to be sure to port your changes to the new version. So open the new customizr/parts/class-header-header_main.php see what changed and port your customizr-child file.

Thank you very much, it worked.

Now I have to find out how to center again logo and menu, since after the changes this explanation is no longer applicable (which was the reason why I copied the file in the first place). ??

Yep I thought at something of the sort.
Get inspired:
https://www.themesandco.com/snippet/center-header-block-items/
https://www.themesandco.com/snippet/center-logo/

That’s the preferred, and suggest, and cheaper way ??

Thanks, d4z_c0nf ?? I think I managed to put it back the way it was!