Implement the parameter override binding in the current Dataflow Gen2 with CI/CD preview.

When you set a default value for a parameter inside the Dataflow, the engine just uses that value at runtime without trying to override it. 

Passing in a different value at runtime means the pipeline activity has to override the parameter.
In the current Gen2 with CI/CD preview, the parameter override binding isn’t fully implemented — so:
The activity accepts the parameter definition.
But when you pass a new value, it either ignores it or fails, falling back to the default

Right now, Gen2 CI/CD parameters are more like constants with optional defaults, not fully dynamic variables you can swap out at run time.