Thanks for posting this, this definitely sounds like odd behavior.
What sites are you seeing this issue occur in? When did it start occurring? Can you send me the site Read-Only links please?
Please send me screenshots of the behavior you’re describing. Is the issue in the exported code only? Or can you see this behavior in the Designer as well?
I was able to see the issue in your site and made a report to the team of the issue. We hope to have it resolved soon.
After removing and re-adding the content class name to the div block on the home page, I can see the styles are slightly different. Thankfully, this doesn’t appear to affect the styles on the canvas:
Doing some more investigation on the .class duplication and it appears another problem is that when I apply flex box to the div and then subsequently remove it (flex box) and return it to a simple display box, the flex box attributes do NOT get removed as I would expect in the output CSS.
Our team has pushed a fix that prevents this issue from happening. That said, your site is still experiencing the duplicate class issue as it was created before the fix.
To resolve this you will need to remove the class names from those sections, clean up the unused classes, then reapply the same styles. Renaming one of the classes may make it easier to find all the instances of it.
Please let me know if this solves the problem, if not, I’m happy to help further.