Those marks are just paraffin.
They are not a defect, in fact, just the opposite, since they are the fruit of a long hard job to protect the edges of the boards, by using an anti-humidity product like paraffin.
This moisture resistant seal gives the flooring a greater guaranty against the humidity problems to which laminate flooring can be exposed.
These stains can be eliminated with a cloth, lightly soaked in water and pH neutral soap. If they do not disappear, try a cloth, lightly soaked in household-grade alcohol.