Hi Da3MoN
If it's a bug we will find the solution. Please, first make sure that you have ATUM add-ons updated, and Woocommerce and Wordpress too, and if doing this the issue persists, please open a private ticket.
I have to ask you to provide us with your website credentials in order to take a look, and probably we will need to download a backup in order to make tests as we have a very strict policy about not modifying anything of our clients' websites.
If you can tell us a product in which you know that this issue is happening it will be very useful.
This is the link to open the private ticket: https://stockmanagementlabs.ticksy.com/
And remember to make a reference to this post.
Best Regards,
Andrea.