@geoffaire - This is a great question. All I know is moving between folders in Mail worked whereas forwarding via my work email did not.
@WayneG - So Thunderbird looked promising but it errored out due to a known Exchange issue. That issue could be solved via one of two add-ons (https://exquilla.zendesk.com/hc/en-us or https://addons.thunderbird.net/en-US/thunderbird/addon/owl-for-exchange/) but I didn’t trust that with my work email and I didn’t know if that would violate our policies.
Thankfully I convinced my admins to put a server forward and now all is working just fine.
Appreciate the help.