WPF Context.DrawImage generates trash on some image sizes

[ShadowTeolog]

Executing code below makes wrong output without any error.
Input with power of two-OK
Immediate saves background to file without ImageBuilder- OK
Draw text on image builder context and save to file without DrawImage- OK
Draw text on image builder context and save to file with DrawImage- text view OK, image on background -corrupt
look like Scanline calculations is broken inside DrawImage
void TestImage(string name)
{
var background = Image.FromFile(name);
var builder = new ImageBuilder(background.Width, background.Height);
var ctx = builder.Context;
ctx.DrawImage(background, new Rectangle(0, 0, background.Width, background.Height));
var bitmap = builder.ToBitmap();
bitmap.Save("test.png",ImageFileType.Png);
}

[slluis]

On which backend?

[slluis]

Ah, WPF