I have the same thing happening with my green slimmer. The new branches are very light green. I was thinking it was because the new branches are closer to my halides.
WOW honestly I have the same thing happening to a pink and blue mili. The first time i noticed the new growth I thought it was the start of a recession...
New growth in sps usually looks like that....it is kind of like a growth spurt. It will change darker when it becomes more established and the "new growth" gets new growth.