Pioneer nexus 900 cd issue

Hi as any body experienced this problem. I use usb and CDs but sometimes I'll put a cd in and it won't read sometimes but won't eject for ages so I sometimes have to turn the deck off then turn it back on to eject the cd then it starts working how it should. It only happens now and then but it's annoying. These are not copied CDs by the way but don't understand why this happens. I've had the decks both checked out and the guys said they is nothing wrong with them. the decks are only three weeks old. Is this just a common problem or would they be something not right.? Cheers.