Hello Debajyoti,
You can expect multiple entries for same Purchase doc in setup tables. The reason is that the same document was changed/cancelled many times during a particular time frame.
You can know this by the value of ROCANCEL. In your screenshot the ROCANCEL is changing from ' ' to 'X' and then back to ' '. If you go to the base table EKPO you can check the code for status of records. (ideally the Trans. PD) you will know that the same document is rejected and released multiple times.
Below is the example where the same record is present multiple times with rejected and changed values in the same extractor.
Please take a look at the ROCANCEL mechanism and you will understand why it is happening.
Thanks
Amit