There seems to be a bug in  

com.mongodb.internal.connection.InternalStreamConnection.openAsync

// code placeholder
public void openAsync(final SingleResultCallback<Void> callback) {
    ..
    try {
        ..
    } catch (Throwable t) {
       ...
    }
    stream.openAsync(new AsyncCompletionHandler<Void>() {
      ..........
    });
}

stream.openAsync is not error handled properly and when this blows up there is no callback. This is causing unexpected error on our side which cannot be handled.

The error usually is 
com.mongodb.MongoSocketException: ......: System error
 

I have attached a stack trace I could provide.