Did the one on the top come from a sealed set with the blue ink from a pen included
on it? That one looks like a pen slipped and accidentally marked it. If it came
out of a sealed set, it could have been an employee's mistake that likely
happened when they were checking the items and is not part of the design since
the other two don't have pen marks.
Perhaps an additional note describing that the pen mark is not part of the design
variation is in order?
France, Centre-Val de Loire
Australia, Queensland