Ignore the previous post, I mixed up my woods. The one that will fade in the sunlight is Chakte-Cok. The previous poster is right, the wood will darken with the exposure to epoxy and although the water based will help to keep its color a little longer, it will eventually darken due to the UV rays that even the best UV resistant varnish will let through. I would follow his advice and accept the color change for what it is.
Excuse me while I go fix my coffee machine!