I am using "Integrate Sendgrid Newsletter Subscription form on WooCommrece Register Page" answer code to one of my previous answers. On Woocommerce account details section of My account page, I have a custom user meta field which is receive_newsletter
which by default has a value of "1" when is checked, like:
When it is unchecked the value will be empty and make it unchecked.
However when I save the changes it will not update.
This would be supposedly an output: