Are you sending to a single user or to a group of users? Using the Post/Page notification or composing an email?
The “Exclude Sender” from recipient list removes the sender email address for the list of users that are selected as recipients (either as specific users or via groups).
When you select more than one recipient (via clicking on multiple users or selecting one more groups) all of the recipients are placed in the “BCC” portion of the email header. Because some email systems will reject (for spam reasons) email messages without an address in the “TO” header the sender’s email address is used for the “TO” header. There is no way to disable this right now.
When you select a single recipient, that specific recipient will appear in the TO header and the sender’s email address will be placed in the CC header. This has been the default functionality since long before I took over development of the plugin and I suppose I could have that honor the same setting as “Exclude sender from the email recipient list” if that is an issue.
