How are “Ghundar” and “Muhammad ibn Jaʿfar” related here?

The Grave Warning Against Lying About the Prophet: Narration, Intent and Critical Duty

• Two distinct narrators, both students of Shuʿbah
• A sobriquet and personal name for the same narrator
• The sobriquet Ghundar is unrelated to Muhammad ibn Jaʿfar
• Ghundar is Shuʿbah’s sobriquet while Muhammad ibn Jaʿfar is a separate narrator