Getting files from gridfs returns files without uploadDate

I have a few uploaded to mongo files through gridFS like that:
``` 
{
    "_id" : ObjectId("52d2660d5500001204a2aac0"),
    "filename" : "sampleFile.jpg",
    "chunkSize" : 262144,
    "length" : 14498,
    "uploadDate" : ISODate("2014-01-12T09:53:17.914Z"),
    "contentType" : "image/jpeg"
}
```
All of them have their `uploadDate` property set to some valid time.
When I'm retrieving it inside the controller with 
```
val gfs = new GridFS(db)
gfs.find(BSONDocument()).collect[List]() map {
        case files: List[DefaultReadFile] =>
          Ok(prettyPrint(obj("files" -> files.map(_.uploadDate))))
      }
```
I get the following response: 
```
{
  "files" : [ null, null, null, null, null, null, null, null, null, null, null]
}
```
which is obviously wrong.