Dataflow Activity Parameters Lose Expression and Get Hardcoded After Reopening Pipeline

Hi svac,

This looks like two separate things to validate:

1. Whether the Dataflow Gen2 public parameters are configured correctly.
2. Whether the Pipeline UI is preserving the expression metadata after reopening the activity.

Microsoft Learn confirms that Dataflow Gen2 with CI/CD support can expose public parameters and that those parameters can be overridden from a Fabric Pipeline Dataflow activity at runtime.

So the first thing I would verify is:

- The Dataflow is a Dataflow Gen2 with CI/CD support.
- Public parameter mode is enabled.
- The Dataflow was saved after enabling public parameters.
- The pipeline activity is using the parameters discovered from the Dataflow parameters section.

However, if the pipeline JSON initially stores the value as:

"value": {
"value": "@pipeline().libraryVariables.xxx",
"type": "Expression"
}

and after reopening the pipeline it changes to:

"value": "actual-guid",
"type": "String"

then that sounds more like a Pipeline authoring/UI serialization issue than a Dataflow parameter configuration issue.

As a workaround, I would suggest testing the same run through the documented parameterized Dataflow Gen2 pattern and also checking whether the expression is still evaluated correctly at runtime after the UI rewrites it. If runtime behavior is also affected, I would raise this with Microsoft Support because the documented capability is to pass parameter values from the pipeline activity, including dynamic values.

References:

Parameterized Dataflow Gen2 - Microsoft Fabric | Microsoft Learn
Use public parameters in Dataflow Gen2 (Preview) - Microsoft Fabric | Microsoft Learn
Dataflow Gen2 data destinations and managed settings - Microsoft Fabric | Microsoft Learn

I hope this helps clarify the difference between parameter configuration and the possible UI persistence behavior.