Newletter subscription activated even if the box is not ticked

Hi, I have a woocommerce store with Klarna Checkout. I activated the Mailchimp integration plugin. In the settings I selected that the tickbox for newsletter is not preselected. But when I did a testorder and did not select the box for newsletter, I still got a mail from Mailchimp to confirm my subscription.

So it seems like all customers are added to the newsletter list when making an order, even if they do not select the box.

What could be the problem? Are there some settings that I am not aware of? I checked Mailchimp side and it does not provide any help there.

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