Check the items list you probably miss 1 or so
saying "I'm 100% sure I have them all" doesn't mean you do untill you check that list. So untill I see your message "I checked every single artefact on my list and I have them all yet no trophy" I won't believe that
Just look at me: 100% in every GoW
Must be something to do with two ps3's and the transferring of data...
For now I am going to enjoy my platinum!