Firstly, the lack of information hiding makes integration developers responsible for understanding how the API behaves. Secondly, the lack of versioning makes it difficult to plan for changes and manage eventual code migrations. Lastly, not being able to safely cache responses increases the number of calls a client needs to perform.
Again, by not offering the ability to version an API, GraphQL passes the burden of understanding the data model to integration developers. An interesting side-effect of not offering versioning is the added difficulty to cache responses and avoid multiple requests that grab the same data.