Thank you for your patience. I've thoroughly investigated the issue and it appears that 'deliveryreport' may be a remnant from an in progress unrelated feature request. From what I'm seeing, the conditions relying on this feature should not currently be present in cPanel 11.28 builds.
I've opened an internal case with our developers regarding this so that the matter can be investigated and resolved. The case number is: 47931
For now, the work around would be what I previously shared with you, adding the line:
deliveryreport=0
to the file: /var/cpanel/features/enabled
This will allow you to enable/disable the "Email Delivery Route" icon as expected when toggling the feature "Ability to Trace an email address" through WHM's Feature Manager.
In regards to the case, when a fix is issued it will be mentioned on
Change Logs with the particular case number 47931
Thank you.
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Brian "Big Boat" Oates
Technical Analyst I
Migration Specialist
cPanel, Inc.