I apologize for any inconvenience caused, and sorry for the late reply, we were on weekend.
In order to know what is happening in your site we will need more info to be able to reproduce it.
Is this happening just with variable products?
Also, I need you to check this before keeping investigating:
- Make sure that you have the last update of your ATUM add-ons.
- If you have and the problem persists, try to deactivate all plugins except ATUM add-ons and Woocommerce and check again.
Please, let us know what happens in order to keep investigating.