Could not read: null for class Artifact for class Artifact

Products

• Rally On-Premise
• Rally SaaS

Issue/Introduction

What could be causing the error; "Could not read: null for class Artifact for class Artifact" on the Iteration Status page after the Workspace Admin added several Custom Fields?

Resolution

This was caused by a name conflict of Custom field being named 'Requirement' which is already in use in the application.  Note that this was reported in an older version of Rally On-Premise which allowed creation of the field with a conflicting name.  Renaming the custom field eliminated the error.