It isn’t really a problem, if you don’t use the algo to adjust colors you didn’t train it to in the first place. The algo shifts high/low saturation areas to how they appear in the reference frame. This is what it is designed to do. Artifacts are usually caused by extrapolation of the curves adjustment to colors it wasn’t properly trained to deal with. If you train the algorithm on those highlights, it will work just fine, and you have the smoothing option to further smooth the gradients where necessary. Like any method it takes experience to use it correctly. If you expect you can use it like some magic wand with zero effort, you’re going to run into trouble. I’ve rarely come across a source and reference that couldn’t be accurately matched with zero artifacts by carefully tuning the parameters.

I would advice everyone who experiences artifacts or other problems, to post the source and reference frames in this thread. I will then create a correction model, which will hopefully have none of these issues, and tell you exactly how I did it.