Eyedropper in the Color Picker window does not grab any color values on Mac/Linux

Trying to use the eyedropper in the color picker window on Mac fails to grab any color values. The colors will only update when hovering or clicking within the viewport but the colors shown aren't correct. They will not update when hovering or clicking inside the color picker or other areas of the editor. When toggling the eyedropper, the 'new' color will default to black.

This feature was working in 4.17.2 but is broken in 4.18.3, 4.19, and //UE4/Main.

This does not occur on Windows.

1. Open any project
2. Select Light Source from the World Outliner
3. Under Light select the bar to the right of Light Color
4. In the Color Picker menu click the Eyedropper icon
5. Move the eyedropper over the color wheel

Result: The eyedropper doesn't grab any color values even when clicking or hovering inside the color wheel and the 'new' color will default to black no matter what color is being clicked or hovered over.
Expected Result: Colors will update in accordance to the position of the eyedropper whether hovering or clicking.