If the hair was not cut properly after Tawaf Al-Ifadah, what is the effect of that on the validity of the Hajj?

Scholars have determined that doubt after completing an act of worship does not affect it, especially if the person experiencing the doubt is prone to it; this is because it leads to hardship. Excessive doubts should be discarded and not given attention.

The Permanent Committee was asked about doubt after completing Tawaf (definition), Sa'i, and prayer, and they replied: "Doubt after completing Tawaf, Sa'i, and prayer should not be entertained, because the apparent state is the soundness of the worship."

Sheikh Ibn 'Uthaymeen mentioned that doubts should be disregarded in three cases: if they are mere delusions, if doubts become frequent, or if the doubt occurs after the completion of an act of worship, unless one becomes certain of the matter.