After completing the rites of Hajj, some people continue to harbour doubts, wondering whether they may have made a mistake somewhere. Many group leaders encourage the pilgrims to offer a dam[1] as compensation, saying that some mistakes may have occurred. Undoubtedly, doing so is contrary to Shariah. This is because you are casting doubt upon your own Hajj without being certain, or having a strong presumption, that you have omitted an obligatory act. If you genuinely have doubts, you should consult knowledgeable scholars thoroughly. If they say that a dam has become obligatory upon you, then you should rectify the matter by offering a dam. Otherwise, you should not. Islam contains no ruling requiring a dam merely on the basis of doubt. Therefore, regardless of what anyone says, you should pay no attention whatsoever to such statements.
[1]. This is called dam-e-khata, compensation for a mistake.