Less sticky rice and lentils

I have a recipe that calls for Rice and green lentils to be cooked at the same time in a rice cooker. I do this and everything cooks nicely, then I add the rest of the ingredients and things taste good.

The problem is that the rice and lentils end up very 'sticky' and the receipie I'm replicating has them being very separate and nice. Once or twice, as if my magic, they have come out great, but I have NO idea what is being changed when I do that.

How do I make 'unsticky' rice and lentils in a rice cooker? Will more water help? Less? salt? sugar? oil?