The Starduster has been in a climate controlled office the last four months, including covering with silkspan and Polycrylic. Wife out of town, so I brought it home this evening to apply base coat white dope. In the kitchen with windows open and I walk by and notice this sagging. Never had this happen before, but I’ve never applied silkspan with a water based product, either. I also notice the top wing with primer does not seem to have the same problem. Any ideas ?? Im going to close the windows before I go to bed. Thanks !!