Hi @Sachin ,
Thank you for posting query in Microsoft Q&A Platform.
I see flatten transformation is behaving correctly only in your case.
Flatten transformation take array values inside hierarchical structures such as JSON and unroll them into individual rows.
So, when array will get flatten automatically rows belonging to that array will get duplicated or flatten. That is what idea of Flatten transformation is.
Kindly check below link for better idea about flatten transformation.
https://www.youtube.com/watch?v=zrjYg2_2Y9I
Please let us know if your expected output is different with sample output data. So that we can guide through steps and transformations to use to achieve same.