Raster paint engine's drawImage() paints a jagged image if width of target is not divisible by 4

When drawing a scaled, ARGB32_Premultiplied image onto a widget or image with width not divisible by 4, with source over composition, the image is painted with jagged scanlines. This does not occur if SmoothPixmapTransform is set or if opacity is less than 1. It also happens when rotated 180 degrees.