Corruption of the Sparkle file would result in the file not loading in Sparkle. This is something about the code Sparkle produces, but I’m not sure about the exact issue. Can you show a screenshot? Some place online where to see the issue? feedback@sparkleapp.com if you prefer.
Should this come up for anybody else, the page background color bleeds through in the scrollbar, even if you have covered the rest of the background with full-width boxes.
I don’t know it’s the same issue, but when I changed the background color on 1 page with the color picker, all the other pages changed to this color.