David, you don’t happened to have soliloquy plugin for slideshows installed, do you?
In my site, the genesis simple sidebars setting in the page editor screen (when changing the page to use a different sidebar) do not save if soliloquy is installed and activated. As soon as I deactivate soliloquy, the sidebar assignment setting will save and work as intended. (so, I just deactivate soliloquy, assign the sidebar, then activate soliloquy again, and the settings still are saved).
