Scheduled Service Change: Authusersmtp & sfmail routing
If a user studies the headers closely they may observe some differences but the overall user experience does not change.
There is no workaround for this issue
To date we have had two systems authoritative for resolving @cornell.edu email addresses. This has caused some issues with duplicated mail and is a unnecessarily more complicated than it needs to be. In the next few weeks Exchange system will become the sole email resolving engine. Authusersmtp and sfmail will be the second group of machines changing over.