It seems that the "Installation deadline to upgrade users or devices that have the superseded application installed" setting does not delay the installation of the application consistently.
In deploying Office 2016 365 ProPlus as an upgrade I have superseded Office 2013 365 ProPlus, and configured the deployment "schedule at" date to 12/31/2015 wanting to give users the option to install the upgrade on their own if they want it right away, before forcing the upgrade at the end of the year.
What I'm experiencing, however, is that the application is installing on its own...on some computers. I've seen it first person, so it's not the case where the user is initiating the installation.
The deployment Purpose is set to Available, not Required. The Automatically upgrade any superseded versions of this application checkbox is checked.
Has anyone else experienced similar behavior with scheduled deployments?