Ra Rules
Ra Jawazi (Permissible Either Way)
In a small number of words, the ra may be read heavy or light.
In a handful of contexts the ra can be read either heavy or light without changing the meaning. The classical example is فِرْقٍ (firqin, "a band/portion," 26:63) — read heavy in some riwayat and light in others. The reader chooses one and stays consistent within a session.