Al-mutashābih is a composite ambiguity: the narrators’ given names may agree in writing and pronunciation while the fathers’ names share the written form but differ in pronunciation; or the fathers’ names agree in both writing and speech while the given names share the written form but differ in pronunciation. Identification must examine the paired name-and-father unit.
The category combines features of muttafiq/muftariq and muʾtalif/mukhtalif, but its hallmark is the combined structure. In some cases the given name is shared and the father’s name is ambiguous; in others the father is shared and the given name differs.
Diagnostic question: Which component matches, and which varies? Once that is established, the technical category and the relevant biographical search become clear.