Share the session log for both use cases.
Check if any error file generated in CASE2.
'stop on error' value at session level was same for both CASE1 and CASE2?
Pls refer the attached session logs
The error you have indicates the user which is configured in the application connection to SalesForce isn't having sufficient priviliges.
What exactly I don't know but it could be a picklist which is incorporated in the SalesForce object.
Please connect with the SFDC administrators to get the issue solved.