My adult bp Kaybe is a cinnamon pastel; and this was very, very apparent when I first got him. As he's grown, his darker colors have gotten much darker, almost hard to tell where the cinnamon brown parts come in... Unless he's under clear lighting, it's hard to tell. He also used to have a very paternless back when he was a baby, like most cinnamons; As he's grown though, his few spots on his back have grown to be a few lines, and less of a black back as expected. He's still a cinnamon pastel; just not as strikingly obvious as when he was a baby. He's still just as gorgeous to me. So yeah, in my opinion, some bps can have some color change as they grow.