Hi Pietro-
Since the plugin is disabled right now, it’s tough to say exactly what went wrong with your logo. My first guess would be that it might have been an issue with Lazy Loading.
You can test this out by adding your logo’s classes to the Exclude Words list on your Performance > User Experience menu. Paste these two lines into the Exclude Words:
kad-standard-logo
kad-retina-logo
Keep in mind that as a Pro Subscriber, you’re also able to access premium support directly from your plugin menu at Performance > Support if you have any more issues.