Graphql-codegen types for field with required extension

When using graphql-codegen to generate typescript types i encounter a problem where when you set a model field to require a certain extension it generates a specific type for it. For example if you set an asset field to only accept “Video” it generates the FileField as VideoFileField type. That’s desired but when i try to use a fragment to query this field i.e

fragment VideoFragment on VideoFileField{
    url
    width
    height
    video {
      thumbnailUrl
      streamingUrl
      mp4high: mp4Url(res: high)
      mp4med: mp4Url(res: medium)
      mp4low: mp4Url(res: low)
      framerate
      duration 
    }
}

…or when it runs generation it throws the same error

Error: fragment “VideoFragment” cannot be spread here as objects of type “VideoFileField” can never be of type “FileField”

Is this a bug or am i doing something wrong?