Echo should not hook into itself, it should just call the relevant code there.
Change 275358 had a related patch set uploaded (by Tahteche):
Echo should not hook into itself with EchoAbortEmailNotification
Provided a patch to this but I was clarified that it is meant to be this way because "the old Hooks::run call resulted in Flow's function being run, this does not."
Should this be listed as a bug then? Help me out if there is anything am missing so I can rework my solution.