Tabs show twice in a tab set
If one or more tabs show twice in a tab set (e.g. there are two 'Features' tabs), it is almost certainly because another tabs app either was or is installed. The most common cause of the problem is an app called 'Ymq Product Tabs'.
When installed, the app removes the theme's original product description code and replaces it with code that duplicates the product description content. This causes our our app to create two tabs for each heading in the product description.
Tabs Studio does not add code to theme files
Remove the code from the other tabs app
Use the settings in the other tabs app to have it remove its code from the theme files and put back the theme's original product description code.
If you're not sure how to use the app settings to remove the code, or if you've deleted the app, contact the app developer and have them remove the code for you.
If you simply delete the app then it will not undo the code changes it made to the theme files when it was installed.
After the code has been removed from the theme files you can safely delete the app.