It's reaching for light even though it can go wherever it wants to in the tank. There's not a ton of flow in there. I only have one Koralia 1050 on a wave maker and the koralia runs backwards half the time so I don't think flow is keeping it out of the light.
For comparison here's a RED one in the same pic so it's not my lighting.
Thanks for the update! I also have a bright red one (which wasn't shipped) a few inches from the two that have lost color. Maybe I'll avoid shipping nems from now on.
From what I've learned and have been told and as someone stated earlier, you need to have its foot in a shaded area and it's main body/the top where the tentacles are in full light...they like their foot to be in a shaded crevice and when this is achieve they are always happiest...that's what mine did at first and it looks awesome now! good luck pm me if you need me to elaborate