«فَالأَوَّلُ: الْفَرْدُ الْمُطْلَقُ»
The first category is absolute singularity.
A fard mutlaq report is one whose isolated transmission occurs at the foundational or pivotal part of the chain. One person's transmission at that link serves as the common basis from which later paths develop.
The adjective absolute does not mean that every single generation must contain exactly one narrator. It identifies the significance and location of the singular original link. That singular route may later be transmitted by a large number of students.
Thus the statement “this hadith now has ten recorded isnads” is not sufficient to exclude absolute singularity. We must inspect the oldest common link from which those ten chains arise.