ISSUE: One or more blocks styles are missing or do not match what is in the editor.
Likely cause: CSS optimizations and Caching
Optimization plugins can do many things to “improve” performance of a site. However they often alter the way code is loaded. Which can result in unexpected consequences, such as the wrong or no styles being loaded.
Is this the first time its happened?
try clearing any caches in plugins, server and browser.
Is the issue persistent?
try disabling any optimisers & caches on the site. Including all plugins or server side functions. Then clear the browser caches or view the site in a private/incognito browser ( has no cache).
If the issue clears then you need to debug which plugin or server function is causing the issue.
Is it still an issue ?
raise a topic in support forums where we can assist you with debugging.