Emails with entries were not being sent.
The entries panel shows they were being sent to an old address, but found nowhere in the current form. The new email address is in place, but the form is still sending to the wrong email.
In order to make it work, I had to make the email field required (it wasn't because we offer to provide a phone number instead) and NOW the email in the field next to the drop-down is used.
I didn't even get to select an email address from the drop down for it to work.