«الْمَزِيدُ فِي مُتَّصِلِ الْأَسَانِيدِ»
This technical category concerns a report for which one of two apparently connected chains includes an additional transmitter shown by critical evidence not to be part of the best-preserved chain.
A longer chain is not automatically wrong. Sometimes the additional intermediary clarifies an actual gap in the shorter route; at other times strong evidence of direct hearing demonstrates that the intermediary has been inserted unnecessarily.
Schematic example: One route is Aḥmad ← Zayd; another is Aḥmad ← Bakr ← Zayd. The number of names is not decisive. The relevant question is whether Aḥmad heard this particular report from Zayd directly or only through Bakr.