Affects Version/s: 7.1.X
0.) Use a vanilla 6.2 bundle with the latest fix pack.
1.) Start the system and create a new site. On this site enable local Staging.
2.) Create a new user (it can be an admin). Login with the new user and create a new web content article and make a Staging publication.
3.) Login with original admin, deactivate and delete the user created in step two and shut down the system.
4.) Make an upgrade to Liferay 7.1, use the upgrade tool.
5.) If the upgrade is finished, start the new system and navigate to the staged site and make a publication.
Result: The publication fails with the below error (full stacktrace attached to this ticket):
2019-07-23 17:12:18.346 ERROR [liferay/background_task-1][BackgroundTaskMessageListener:173] Unable to execute background task
com.liferay.exportimport.kernel.lar.PortletDataException: No User exists with the primary key 20555