Vision text detection is resulting in calling OnSuccessListener multiple times

Question

I am using the sample code of mobile vision to perform text detection on an image. Here is the code

private void detectInVisionImage(
            FirebaseVisionImage image,
            final FrameMetadata metadata,
            final GraphicOverlay graphicOverlay) {
        detectInImage(image)
                .addOnSuccessListener(
                        new OnSuccessListener<T>() {
                            @Override
                            public void onSuccess(T results) {
                                shouldThrottle.set(false);
                                VisionProcessorBase.this.onSuccess(results, metadata,
                                        graphicOverlay);
                            }
                        })
                .addOnFailureListener(
                        new OnFailureListener() {
                            @Override
                            public void onFailure(@NonNull Exception e) {
                                shouldThrottle.set(false);
                                VisionProcessorBase.this.onFailure(e);
                            }
                        });
        // Begin throttling until this frame of input has been processed, either in onSuccess or
        // onFailure.
        shouldThrottle.set(true);
    }

For some reason, the onSuccessListener is being called so many times ( as if it is continuous detection). Although I call the detectInVisionImage only once on an image.

Why is this happening? A bug?

Thank you