I have the default layout set to right sidebar. If I change a post (happens to be on the homepage) layout to full width, it breaks the homepage, which then also shows full width. This only happens if the homepage slider is not turned on. When I turned it on, the homepage goes back to right sidebar.
Otherwise - awesome theme, keep up the great work!
I hope you are well today and thanks for posting here.
I have tested it on my test site using latest version of Sparkling theme as you have described above but it worked fine for me without any issue.
Please make sure you are using latest version of Sparkling theme.
This can be due to plugin conflict on your site so please try temporary deactivating all plugins and see whether everything works fine and then enable the plugins one by one to see which plugin is conflicting if any.
Could you please share the page URL from your site where it’s not displaying correctly so that i can troubleshoot it?