I have not seen the crack myself and cannot comment on the crack. If the casing is plastic then plastic injection molding process is involved. Plastic resins are heated and melted inside the molding machine and injected into a mould to form the part (the casing). Somewhere inside the mould the melted plastic has to meet and then cured to form the part before the mould is opened. The place when the plastic met and cure formed a 'flow line' and could be visible depends on the color and lighting.
If you can feel the line with your finger nail, it is a crack, otherwise it could just be a 'flow line'
If you can feel the line with your finger nail, it is a crack, otherwise it could just be a 'flow line'
