Being a Stack Exchange evangelist, when my grandma had a cooking question, I signed her up for Seasoned Advice. She got the following joining notification:
Notice the "Welcome to Stack Overflow!" message. People joining the non-SO sites might find this strange.
EDIT (July 22):
the notification history for the account now looks as follows:
There is still no Seasoned Advice notification. Even if SO was joined two days later (after the screenshot was taken) that doesn't explain the lack of SA notification.
ANOTHER EDIT (July 22):
I tried clicking the user page link, and I got This nonexistent page.
I think there has to be a problem, even if it doesn't always occur.
The SO account was apparently created last year. So that was the source of the confusion.