Its normal. Especially in light colors like yellow and white, because some of those colors don’t set in immediately. The artist has to guess whether its in solid, until it begins to show. Solid Black work is common too, because when your pores close back up after an hour or two there may be slight holidays. Usually a good artist can avoid that by slowing down, but not always. Sometimes the touch ups are caused by how you heal, and how you take care of it. My touch ups are always free.