Dynamic children in list view not loading

I'm trying to display a list of references.
I have the collection called "judges" that hold a list "to_judge" of references of the collection "construction tasks". So a jury-team judges different construction tasks and I want to display these task for each jury-team.
First I query the collection "judges" and under ListView I created dynamic children. In the container under ListView I tried to query a document reference with the created dynamic children to fetch the constructionTasks for the specific jury-team.
During debugging I can see that it fetches the correct references but during display I only get the loading screen.
Does anyone have an idea how to get rid of the loading screen? I'm using firebase as database.