Is this a deficiency?

Never layer soil, always mix it before adding it to your pot. Layers can cause shock to the plant by growing one way then suddenly growing into something (soil) that is completely different. The spots are from misting, misting is completely unnecessary. It should only ever be done as an emergency solution for chronic deficiencies of trace elements. If you want to boost your plants immune system, fulvic acid, amino acids and humic acids applied to the soil will really get your plant zinging along. Hope this helps, Organoman.