It seems that Webflow had recently updated the class duplication and it’s totally breaking it on my websites.
Here is the problem:
I select a previously created element (in my case I’ve tried only with div component) and I click on the duplicate class button, then I rename it with a totally unused name class. Great I can see my new class created and associated with my component. Then I wait a little bit to see the green check mark to be sure my modification is saved. Once it turn green I refresh the page… And here is the problem! My component doesn’t have any class associated to it and my newly created class doesn’t exist.
This is for me a huge problem I’m working on websites that really need this feature in every day life for development.
We were able to reproduce the issue and our team is looking into this. It looks like you can workaround this for now by pressing CMD+S (CTRL on Windows) after duplicating a class. This manual save will ensure the change is properly saved.
Thanks for your patience and we’ll report back when we have more information for you.