Usually when a clean cat begins to soil inappropriately there is a medical reason. However, I think your cat is reacting to some kind of latent stress based anxiety. Cats are very intuitive and can easily pick up on our emotions and fears. Atmospheric changes in humidity are possible causes as well.
I suggest you get Feliway at
www.catfaeries.com the plug ins and the spray. Also an enzyme cleaner to disinfect the comforter. Then spray the feliway that simulates her marking scent (to her -not you).She has chosen your bed to mark because she fears being moved and she wants to mark that spot so everyone will know that it belongs to HER. In her own cat mind she thinks that will keep her from being moved again.
I sincerely hope that we will have a peaceful summer this year. I am living in West Palm since 1980 and never saw a hurricane before 2004. How about you.
PLease let me know if you need ANY further help.
Dedicated to Cats and the people who love them!
Please press ACCEPT if my answer was helpful and leave feedback Thank you! Terri