1. Does the issue happen only while in case worker portal and work fine if in designer studio / case manager ?
2. I assume the validation fires when you submit the flow action and the error is displayed. The refresh harness probably calls - clearMessages . The validation will fire again only when you submit the flow action again. What is your expectation here ? Do you want the messages to be retained when calling refreshHarness ? Did it work before (in previous version) and break now ?