Default GP Child theme breaks WP gallery

As a good practice I always use a child theme. In the case of the GP theme, I use the default GeneratePress Child Theme (Version): 0.1 which I downloaded from this website. No adjustments made to this child theme, all CSS removed, no plugins active, the default WP gallery always shows as 1 column. When I activate the GP theme itself (so not the GP Child theme) the Gallery shows up correctly with the 4 columns I want.

https://postimg.cc/1ngK74KC

I always use a child theme like this to avoid future changes in the main theme.