Can Onyx for Snow Leopard cause MobileMe iCal sync issues?

I just installed the latest version of Onyx. I've run it twice and each time I've found that I end up with duplicate copies of iCals on all synced devices - iPhones, desktop, iPad and Laptop. Is this just a coincidence? I've used Cocktail for years and never have experienced this problem. I'm running Onyx basically as it comes. However, I may have changed some setting in the Cleanup section. Is this a just a coincidence, bug or how I may have it optioned?