Copy activity dynamically populated additional columns error when using Expression values

Hi patto_uon ,

Thanks for the clarification. To confirm, expressions such as @{formatDateTime(utcNow())} are only evaluated when they are authored directly inside the pipeline. When the same string comes from external metadata, Fabric treats it as normal text, which is why you see the expression printed instead of the evaluated value.

So when I mentioned a “pipeline-ready expression format,” it meant that your metadata should contain the information needed to build a valid expression, but the pipeline still needs to convert that metadata into an actual expression before passing it to the Copy activity. Currently, the service cannot execute expressions coming directly from metadata files.

To achieve a metadata-driven approach, a small preprocessing step in the pipeline is required to translate metadata into real expressions.

Thank you.