It is kind of hard to tell from that pic where the coral in question is but I can see where it is not. I have a yellow fiji leather that has the crown 4-5 inches from the waterline directly under one of my striplights, It is seeing more than 300 par as an estimate. I left it by the bottom of my tank for about a month when I first got it and it stayed brown but now it is bright yellow. It needed that light to color up.
If that tank is lit by a single kessil than you may want to try moving it closer to center, higher, or slowly turning up your kessil to see if you get a better response from it. Just keep an eye on that beautiful BTA, I do not think it would be worth ****ing him off.