2540312 - Workflow Rule To Update A Field Failed With Error Message "Change Of Field Is Not Allowed"

You created a Workflow Rule ABC (where ABC is the Workflow Rule name) to update the field XYZ(where XYZ is a field in the Sales Quote)in Sales Quote 123(where 123 is the Sales Quote ID) but the Workflow Rule Failed.
This workflow Rule has failed for some instances while have executed successfully for others.
When you check the error message in Workflow Log it states- "Change of XYZ is not allowed".

SAP Cloud for Customer

1. Go to Administrator work center.
2. Go to Workflow Rules view.
3. Click on the Cogwheel icon and select Workflow Log.
4. Click on Advanced Search icon and search with Status Failed.
5. In the Status column click on Failed hyperlink.

The error message shown here is "Changing Status not possible; field is read-only".

Workflow Rule ABC failed for some instances because the update of field XYZ is not possible if Approval Status is "In Approval".
And it executed successfully for other instances because at that point of time the Approval Status was not "In Approval".The change of Approval Status can be seen in Changes facet for Sales Quote 123.

This is the expected system behavior. When the Object is set to "In Approval", the whole object is locked for changes until the Approver has a change of checking it.

Approvals Help Center Document

Approval Process ; Lock ; Failed ; Changing Status not possible; field is read-only , KBA , LOD-CRM-EMP , Employee , How To

SAP Cloud for Customer core applications 1708 ; SAP Cloud for Customer core applications 1711 ; SAP Hybris Cloud for Customer add-ins 1708 ; SAP Hybris Cloud for Customer add-ins 1711