What is the ruling on the phenomena of "disuniting the group" (فك الوحدة) and "the ختمة" after a person's death, and are they considered innovations (bid‘ah)?

Visiting graves is legislated, but singling out a specific time for it with the intention of gaining merit or greater benefit at that time, such as gathering in the deceased's home or at the grave, or during the fortieth-day commemoration, is considered an additive or innovated bid'ah (innovation). The same applies to gathering to recite the Qur'an and dedicating its reward to the deceased.

As for completing the recitation of the Qur'an and dedicating it to the deceased without a gathering for that purpose, the preponderant opinion is that it is permissible and its reward reaches the deceased, Allah willing.

Reciting the Qur'an at the grave without a gathering is deemed disliked by the majority of scholars.

The fortieth-day commemoration (where the family of the deceased recites the Qur'an, visits the grave, or gives charity forty days after death) is a reprehensible innovation because it was not transmitted from the Prophet (peace be upon him), nor from the Companions, nor the righteous predecessors.

One must be wary of innovations and adhere to what the Prophet (peace be upon him), his Companions, and the righteous predecessors were upon, for every innovated matter is a bid'ah, and every bid'ah is misguidance.