A former IPS officer Dr. Dalbir Bharti writes in his book the constitution and criminal justice administration in the page 16 that
...in a research it has found that out of 2685 verses in the Manusmriti only 1214 verses are original and remaining 1471 verses are interpolated. The researcher has described how the interpolated verses of the Manu Smriti either contravene the views of the Manu as expressed in the other verses or are irrelevant to the subject matter where they are places...
Being an IPS is not a piece of cake in India unless you belong to reserved category. So he must have read the research somewhere regarding the same.
Do we have any research paper or any content which shows or argues how Manu Smriti is interpolated. And possibly what are those possible verses if interpolated according to the researches.