Hello,
I order to confirm the behavior, I ran a test specifically for this and any new contacts that were not previously in the system will receive a welcome email. In addition, contacts that were opted out will also receive a welcome email when they are added to your list by this method.
What you may have run into is if a contact is already active in your account and you're simply adding a new list to the contact, that does not cause an email notification to be sent. Given that the opt-in date on the example contact you provided is Nov. 2nd, I think that this is likely the case that you are seeing. The easiest way to test the notifications is to create a brand new contact, and then you can opt that contact out and resubscribe it to see that the welcome email is sent again.
If you have any questions, please let me know!
Sincerely,
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