@retsifp figured out today that setting the notification LEDs on the FP2 to mixed colors does not work. Unfortunately at the moment the problem is still kind of tricky for most users to reproduce, as you need to have your device rooted in order to get the notification LEDs working in other colors than red.
Anyhow, while natively the LEDs are red, green, and blue (RGB), mixing them should make it possible to have a wider range of colors available. However, when setting the notification LED to mixed colors, it seems that the blinking interval of the different colors do not overlap but have a different frequency, leading to some kind of random color game instead of to the desired mixed color.
How to reproduce:
(Note: You have to have root access and already deployed a fix/workaround to have LED colors working)
Use LightManager, a LED Tester, or an app that supports mixed colors. Set notification LED to a mixed color.
Instead of getting a mixed color (e.g. orange, or yellow) two different colors blink at different and non overlapping intervals.
While the first blink still gives the proper color, then the colors "split".
This is what I got when setting the LED notification to orange