I read from another user who submitted a support request that Microsoft is working on some of the scheduling functionality which explains the difference in behaviour between the UIs. https://community.dynamics.com/365/b/nocodecustomizationconcepts/posts/how-to-change-default-appointment-behaviour-in-unified-interface When testing this, it is also worth noting the difference in behaviour when the Appointment is synched with Exchange/Outlook: Dynamics 365 for Outlook (Client Side): Appointment is synced as draft and invitations are not sent to attendees. Dynamics 365 App for Outlook (Server Side): Appointment is synced as scheduled (regardless to the behaviour you've identified) and invitations are sent to attendees. Hope that helps.