This is normal, when you mix the 2 part resin together the resin will start to become cloudy- and toward the end of the mix, it will start to turn clear again.
1.  When mixing make sure you resin has had a warm water bath. Warm resin will mix faster and easier. Make sure to mix slowly, mixing fast will incorporate air bubbles and make your resin look cloudy while mixing.  Sometimes resin will remain cloudy until applied to artwork and torched- at which point it will clear up.
2.  Make sure that you are mixing no less than the minimum 2 oz of resin.  Mixing less than this can cause resin not to set, by sticky or soft.