2 Euro Coin Portugal 2002

I think what Sonicattitude is referring to is the way the stars around the outside on the obverse are partly on the exterior cupro-nickel ring and partly on the brass central core.

I've examined the 2002 Portuguese 2-euro coin in my collection and it's similar to that pictured above, although not quite as pronounced.

Like the ring of dots around the Queen's portrait on most British bimetallic £2 coins, I think this is more of a design fault than a collectable error. The ring of stars just happens to be positioned where some of the stars will get bisected by the groove between the two metals if the strike is not perfectly central.