Hi all. I did this mural on a North facing exterior wall that does not ever get direct sunlight. Something has caused the smoothed-out colors (on the right) to bleach in spots, resulting in the current state (pictured on the left). They swear they have not treated the wall or powerwashed it or anything of that sort, and again, it gets no direct light. My speculations are as followed: 1, perhaps some interior paint was mixed in w mostly exterior grade paints. If that were the case, what would happen? Would the interior parts just be less durable? 2, this was a rush before winter job, worked on in between cold days. I only painted when it was above 50degrees F. Could cold/curing be a factor? 3, I clear-coated the entire thing in a compatible flat UV protection, which did not show any immediate issues or conflicts. Could that factor in? The mural is only around 10 months old or so. Makes no sense to me. I am eager to correct the painting, but I want to know what went wrong so I know how to fix it FOR GOOD. Thank you all.