3722203 - Draft activation fails for LargeBinary in CAP Fiori Elements app with error “$batch failed”

When saving a draft document larger than 500 KB in a Fiori Elements application created by CAP CDS, the file is stored in the draft table already, but not copied into the active table during draft activation and the UI remains stuck showing a loading indicator.

In the browser console there is error message:
"Error while saving the document - Error: Error: HTTP request was not processed because $batch failed
Error: Error: HTTP request was not processed because $batch failed"

Note that:
This issue happens with:

• The usage of library "@sap/cds": "^9.0.0" and "@cap-js/hana"
• No explicit dependency on hdb or @sap/hana-client in package.json.
• No custom event handlers are involved and the logs do not show any backend error

• SAP CAP – Compiler and CDS language
• Fiori Elements app

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