Hi
Duplicate properties are not allowed in a XMP packet. This is mentioned in XMP Specificataion part1, section 6.1. A property can be replaced with an attribute to rdf:Description element(see section 7.9.2.2). So both these variations for the same property can't exist in the one XMP packet as that will mean duplicating the property. Only one of these variations is allowed for a property. So your pdf has an invalid XMP packet.