This is actually normal for non dairy kefir. Since most nut milks are made with mostly water it separates quite easily. This doesn’t diminish the product in anyway. Stir or shake it up, or blend it into a smoothie. You might want to taste your batch while it’s fermenting. As soon as it sour or tart it is done and should be placed into the refrigerator to keep it from continuing to separate. Coconut milk made from canned milk doesn’t usually separate and stays creamy and thick.