full maple necks are often finished in a hard finish and the finish goes over the frets. Then, the frets are beveled, leveled, crowned and buffed. Sometimes the finish isn't cut off perfectly and voila, you get what you're seeing. Any luthier worth his/her salt should be able to clean this up and buff this out. Or, just deal with it and ignore it. As long as the string doesn't feel raspy over the frets, you're fine.