Understanding Background Execution

Workflows run in a background session without page session state or a logged-in user.

The APEX engine manages the progress of workflow instances asynchronously in the background. It processes each instance’s next activity in a distinct engine session with no logged-in user. A workflow engine session is also different from the user session created for each end user of your application’s pages.

By design, two consequences are:

Therefore, any value your workflow depends on needs to be: