no usually the opposite, too much light will make them lighter.
I am not how long you have been on LEDS, but when my brother changed from his ATI PM to vertex LED his corals darkened for a month or so due to the shock of the change.
how long have you used the LED?
did you change recently?
does your LED have any red spectrum? Pinks can suffer due to the missing spectrum.
my brother used CIE Chromaticity Meter to measure the light spectrum ($10,000 piece of equipment) on his vertex with the following results
and just for reference here is his birdsnest under T5
and under LED 75:100:100 (w:b:rb)
he will be adding some red and violet leds when vertex release them in Aus to get the pink pop back in the birdsnest