Lead Developer
A couple months back WP.org forced all themes to the the custom_logo theme_mod in their themes. theme_mod settings are only applicable to the theme they were set with, which means they disappear when themes are changed, even if it’s a child theme.
Terrible user experience in my opinion, at least for options like the logo, copyright etc..
I’ve been talking to a couple developers and have come up with a function I need to test a little which should use the parent theme theme_mod option if the child theme option isn’t set.
So yes, long story short, Roberto nailed it. The logo needs to be re-uploaded in the Customizer when the theme changes.