Opening the color picker causes values to change

Opening the Color Picker for some color variables causes them to change each time the color picker is opened.

Tested with: Light Color and the Albedo variable on ExponentialHeightFog
Does NOT occur with the Directional Inscattering Color variable on an ExponentialHeightFog asset

Also hitting this issue at 3647309 in Main.
This is not occurring in 4.17.2

1. Create a blueprint First Person Shooter template
2. Drag a point light into the viewport from the modes panel
3. Under Light> Light Color > Click the color box to open the color picker
4. Put in the following values:
   1. H: 123
   2. S: 0.9
   3. V: 1.0
5. Click OK to close the Color Picker
6. Reopen the Color Picker

*Result:" The entered values change to different values
*Expected Result:" Values stay the same as entered