Very likely, yes. If the baking powder and baking soda aren't distributed evenly, you'll often see a white patch in the muffin/scone. Which is a clump of powder or soda.

Baking soda is salty, I often omit the salt entirely when using it.

I just did an internet search on the subject, and I think I may have an answer. There are apparently baking powders that contain aluminum and some don't. I normally buy name brand, but was in Aldi's and picked up one from them. I just looked at the container and it says aluminum something on the ingredients list. Needless to say, I tossed the whole container. Will go back to my other brands and test the recipe again. Thank you for your answers.

I see you have come up with a possible answer but still, here is my input. I usually don't sift but do give the dry ingredients a good stir with a fork or whisk to make sure that salt, baking powder and any spices are well distributed. For scones and such, usually you just stir the wet and dry together enough to get the dough evenly moistened so that's not enough to ensure spreading out the baking powder through the mix if you you haven't mixed the dry ingredients.

I'm another one that whisks the dry ingredients, I do it thoroughly!

Baking powder that contains an aluminum salt is a double acting baking powder. That means it gives a little lift when you mix it with the wet ingredients but doesn't really "work" until you bake the item. Some double action baking powders contain another agent to delay the leavening until heated.

I don't sift either, but I do crush baking powder/soda in the palm of my hand before adding it, in case there are any lumps. I measure, then pour the spoonful into my hand and use the back of the measuring spoon to smush it. Baking soda almost always has lumps, IMPE.

I put the baking powder through a very fine strainer to get rid of any little lumps.

And not all baking powder has aluminum in it. I use the aluminum free kind.