GE 4.5.1/GVH 2.6: Default theme not inherited by child sites?

I've not set a default theme other than 'All Available Layers' in a while, so I'm not sure if this is a new issue or even if it's expected behavior, but it seems like it should work.

 

I set my themes in the parent site and made one of them Default theme, but in the child sites, the Default theme hasn't changed from 'All Available Layers', so I had to manually set that in the child site. Bug?