Issue
After upgrading Tableau Server to the May 2023 maintenance release or Tableau Cloud 2023.2.0(20232.23.0701.0006), the "System error: null" occurs when running an existing flow which contains non-English characters, such as Chinese, Japanese or Korean in the Output filename.
If you publish a new flow with CJK characters in Output, the flow is published successfully but running it on Tableau Server will cause the above error.