I am having an issued with customer profiles not updated after they unsubscribe. Customers are supposed to be unsubscribed when they click Unsubscribe in an email, but this is not happening. For anything I saw this was happening, I tried to manually unsubscribe them, but that did not work either. This is a serious issue for complying with anti-spam regulations.
Shopify support is working on it, but I wanted to share this so you can check your accounts if you want. I would advise checking even if you use a third part email sender.