Setting parent of instantiated object fails (Error: setting parent of prefab is disabled...)

I have an object that I instantiate and I immediately attempt to set it as a child of something, which fails with the error "Setting the parent of a transform which resides in a prefab is disabled to prevent data corruption". The pattern is something I've written many times before, and I understand what the error is saying, but I don't see how this is possible given the object has been instantiated and so shouldn't be a prefab. Here is the code:

  var myRecipe = Instantiate(Resources.Load<recipe>("Recipes/woodenWall"));
  myRecipe.transform.SetParent(transform);

The second line is the one that fails; unity takes me right there in the stack trace.

I can see the instantiated object in the hierarchy, and it is definitely the same object as the one stored in the variable "myRecipe", I just can't set it's parent (note: I can change to and get the same error). Has anyone ran into this problem before?

Thanks.