Okay, I have a great bug for you to see. It kind of drove me nuts for a bit till i figured out what was happening.
On the color picker,
1)Enter into the HexColor Field. “AAAAAAFF”
2)Click out of the Input box, It will change to “686868FF”
3)Click the mouse into the inputfield and back out of the inputfield, the HexColor will reduce to “232323FF”
This will continue to reduce the Hex value each time you click out of the inputfield text box. This happens for all hex values except for FFFFFFFF and the alpha channel.
I verified this repro with Launcher 4.5.1 and a new c++ first person project. I used the color picker in the point light and the directional light details panel.
I hope this helps and let me know if you have questions.