Root Cause: An external task in a Workflow triggered the following task because of it's incorrect status. This is a defect of the Automation Engine version 12.0.3 and prior versions.
Update to a fix version listed below or a newer version if available.
Fix Status: Released
Automation Engine 12.1.1 – Available
Automation Engine 12.0.4 – Available
Automation Engine 12.0.3 HF3 – Available