I used to have trouble with it setting in that the cream would settle into layers, with actual butter at the top. (davidlebovitz.com)
For all those asking re substitutes, for coconut butter you could use peanut butter or other nut butters not actual butter as the textures and consistency aren't the same! (realfoodliz.com)
I will substitute actual butter however since I am not a vegan. (ohladycakes.com)