Subaru 2003 2.0XT turbo problem

dear Subaru community, right with my first post here I will start with a problem immediately. so I have been in possession of a Silver Subaru Forester 2003 2.0 XT for a week now. only unfortunately I have problems with turbo at the moment. when I go and the car is cold the turbo pulls quite normal yet as soon the car on temperatures is so 5-10 minutes the turbo stops pressing and the car drives as if it has no turbo. pulls normally high without jerking etc. stop all without turbo pressure. any of you had the same problem? order knows what it can be? gruss alex