Have never had it happen with Posette, but when I was using Rena's composite of Vic/Posette the other night and also had Vicky in the window, I had it happen over and over--kept thinking I was losing my mind LOL. I was trying to set the composite back to 'sort of' Vicky so I had a more or less clean slate to start with her, so had the same map on Vicky and the composite to try and do that--and strange things would happen when I would render G.