Getting error "{"code":"BadRequest","message":null,...while debugging a DataFlow in a ForEach loop

While running Data Flow from a for each loop the parameter of data sets are not being passed( strange enough, only for the Sink). Tried creating a pipeline with the same DF and it is successfully running. Again while trying to call the pipeline from loop, the error returns.

There could be a question why DF is being called from inside a for loop, the reason is we need multiple JSON output from multiple CSV sources.

Error Details :

{
"code": "BadRequest",
"message": null,
"target": "pipeline//runid/************************",
"details": null,
"error": null
}