deviating
Deviating means to go out of the normal way that something is done. When you deviate from the standard recipe, you might end up with a recipe that is not very good.
The recipe calls for baking the cookies on the bottom of the oven, but the deviator decided to bake them on the top.
The deviator decided to add a new ingredient to the recipe, and it ended up ruining the entire batch.