Hello, @sebastien.vassaux first it seems normal to me that you have documents without uid. I can see in your content definition that you're having some custom types (team-member) that do not have any uid set up or restrict your query to only blog-post. You might want to change your code to handle those cases.
For the problem of seeing a small set of documents (20 docs), this is the normal behavior of the GraphQL API. You can see more about pagination here : https://prismic.io/docs/graphql/query-the-api/paginate-your-results
Seeing all documents in one query was a regression. We are progressively deploying fixes and your repository had this regression, you're now on a stable version of the API.