Right now my daughter sleeps in her baby box at night but I’m going to transition her to the basssinet portion of her pack n play. We have a mattress protector and sheets on it and they’re definitely not too small but sometimes it seems like the mattress sections don’t lay flat. In particular the middle 2 don’t feel like they’re lined up correctly. Has anyone had this problem and can give me some tips? Sometimes it happens just the bare mattress in there too.