Hi Janet! I've never seen one of your quilts that didn't hang absolutely flat! Is wool the only batting you used, or is it layered on top of a cotton base? Just wool doesn't give much support for a quilt that will be hanging, but I would think that would be more likely to cause wavy edges than cupping.
Could it be that maybe your binding is causing the cupping? Would it be worth replacing the binding? I know that's a PITA, but if this is as good as your usual work, it might be worth the effort to satisfy a judge. If it's a detailed binding, like you often do, that would be a difficult decision.
Maybe it would be worth trying some starch??? Please let us know what you decide to do and if anything worked for you.