Some artifacts may be visible from the compositing, but you have to look pretty closely to see them.
The color table threshold was raised for these images, reducing the amount of noise visible in the images.
Note: There is an interesting artifact worthy of mention and clarification, and that is as Venus crosses the solar limb, the limb appears to be visible through the planet in some of the imagers (most notably the ultraviolet channels). Discussion with the scientists who built the imagers suggest this might be 'crosstalk' between the readouts of the four CCD panels that make up a complete image. It is an artifact of the imaging system.