Tax added twice

Can you publish or send us a screenshot of your WooCommerce – APG Weight and Postcode/State/Country Shipping configuration?

Probably your problem is generated by the shipping classes configuration.

Kind regards.

Sure here it is https://imgur.com/Jh59R09

Change the shipping clases configuration and just select All shipping classes.

That’s all.

Kind regards.

I don’t want to do that because I just want that shipping method for the products in those specific shipping classes.

Wich classes do you have on C2 configuration?

For C2 I just have one shipping class (gift vouchers)

Did you try the last update?

yes, but it did not fix the problem.