When switching CICS sessions the data is refreshed and any uncommitted updates are lost.
Article ID: 106371
TPX - Session ManagementVman Session Management for z/OS
We have users that have multiple sessions to the same CICS application. They will enter needed changes in one CICS session, switch to another CICS session of the same application to validate the changes, switch back to the update CICS session but the updates are no longer there. This is not the case with a TSO session.