3805301 - 500 Internal Server Error : POST /keyuser/flex/all/v3/actions/condense/

• UI5 Flexibility Variant Management changes do not persist in a Fiori Elements List Report app on Cloud Foundry using a standalone approuter and BtpServiceConnector.
• Saving a variant initiates POST /keyuser/flex/all/v3/actions/condense/ which fails with 500 Internal Server Error:
  
  http request:
  
  fetch("https://XXXXXXXXXXXXXX.cfapps.us21.hana.ondemand.com/keyuser/flex/all/v3/actions/condense/..?sap-language=en-US", {
    "headers": {
      "accept": "*/*",
      "accept-language": "en-US,en;q=0.9",
      "cache-control": "no-cache",
      "content-type": "application/json; charset=UTF-8",
      "pragma": "no-cache",
      "priority": "u=1, i",
      "sec-ch-ua": "\"Chromium\";v=\"152\", \"Not?A_Brand\";v=\"24\", \"Microsoft Edge\";v=\"152\"",
      "sec-ch-ua-mobile": "?0",
      "sec-ch-ua-platform": "\"Windows\"",
      "sec-fetch-dest": "empty",
      "sec-fetch-mode": "cors",
    },
    "referrer": "https://XXXXXXXX.cfapps.us21.hana.ondemand.com/..../index.html",

• Cloud Foundry UI Flexibility Service functionality
• Fiori Elements List Report application
• Standalone approuter
• UI5 Flexibility service via BtpServiceConnector

UI5 Flexibility, variant management, BtpServiceConnector, Cloud Foundry, Fiori Elements, List Report, /keyuser/flex/condense, HTTP 500, variants not persisted, key user flexibility, standalone approuter, multi-tenant, Work Zone, persistence error, flex service , KBA , CA-UI5-FL-CLS , Cloud Foundry UI Flexibility Service Functionality , Problem