I am looking for second opinion on my understanding of subscriber key in SFMC.
In my environment on SFMC SK is
I am trying triggered email send from SalesCloud. The email goes good on the email address for the first time. Now when I change email address on lead and try to send email it does not go to it. I receive no error from SFMC in response, however, I also do not see anything request queued up in SFMC.
But when I send again to previous email address it goes well.
Is SFMC binding email address to subscriber key or it is its standard behavior?