An update and an apology - we have learnt that this feature requires the hidden processing screen to be included in the site map so that the process is included in the list of Automation Schedule Statuses, and therefore is covered by the 'Initialize Scheduler' action. This is resolved in our upcoming 2020.4 release.
If you want to get the benefit of this now, you can manually add the hidden screen MP.PP.50.26 (url: ~/Pages/MP/PP/MPPP5026.aspx) to the site map yourself - we recommend not populating the Workspaces or Category fields so that it doesn't appear on users' menus.
