Why do my widget's components become None when I make a child class from it?

I’ve got a custom widget that owns an Image component, and in PreConstruct does some stuff to it.

I then make another Blueprint, derived from the widget type. In that Blueprint, I do not add or change anything. It’s an empty, plain child.

However, when I spawn the derived Blueprint instead of the Base one, I get errors within the base type’s PreConstruct about the Image component being None. These errors still happen if I change from PreConstruct to Construct or OnInitialized.

What am I doing wrong?