Large hitching is occurring when click dragging inside the color wheel of the color picker or scrubbing RGB, HSV, and Value/Saturation sliders.
I am only able to repro this issue in Binary builds. 4.12.4 and 4.13 binary produce the same issue, but the P4 builds of both do not.
This issue does not occur in P4 //UE4/Main @ 3035542
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-32785 in the post.