I guess I am not explaining this properly.
There is no issue with Sendgrid, it is sending emails just fine. It is just in sendgrid that I see that the server is sending emails to that email address, ro...@servername.c.projectname.internal. They are bouncing because it is not a real email address; and judging by the format of the email address, it seems to be a server default email address. It is sending an email every day, at the same time, just one email.
I had assumed that it was the email address for the root user, which is what I tried changing, but to no avail yet.
Does that make sense?