Emgu Opencv C# ConvertTo different results

I'm having issues getting C# Emgu.NET (opencv) to produce the same results as similar C++ code. It is pretty simple, I am just opening an image as a 16UC1 and converting to 32FC1. Here's the C++ code:

inImg = imread(inPath.c_str(), -1);
cv::Mat fltImg;
inImg.convertTo(fltImg, CV_32FC1  );

I'm saving the raw data bytes to a file like this:

std::ofstream fout;
fout.open(filename, std::ios::binary | std::ios::out);

fout.write((char*)img.data, img.rows * img.cols * bytesPerPixel);

fout.close();

I'm saving both inImg and fltImg for debugging purposes (2 and 4 bytesPerPixel respectively)

On the Emgu.NET side:

var handle = GCHandle.Alloc(pixelValues, GCHandleType.Pinned);
try
{
    var ptr = handle.AddrOfPinnedObject();
    var mat = new Mat(new Size(height, width), DepthType.Cv16U, 
                    1, ptr, width * 2);

   var convMat = new Mat();
   mat.ConvertTo(convMat, DepthType.Cv32F);
}
finally
{
    if (handle.IsAllocated)
    {
        handle.Free();
    }
}

I'm saving the raw files int the following way:

private void SaveDebugImage(string filename, Mat img, int depth)
{
    byte[] data = MatData(img, depth);
    File.WriteAllBytes(filename, data);
}

private byte[] MatData(Mat img, int pixelBytes)
{
    var ptr = img.DataPointer;
    int size = img.Rows * img.Cols * pixelBytes;
    var outBytes = new byte[size];
    Marshal.Copy(ptr, outBytes, 0, size);
    return outBytes;
}

Comparing the first (16 bpp) images, they are identical, but the ones after the call to convertTo result in different images:

C++ C++ output

C# C# output

Any ideas on what could be going wrong?

Thanks!