A transmitter may be said to narrate from someone called Muslim and to have a student also called Muslim. This does not necessarily mean the same Muslim appears on both sides or that the chain loops back upon itself.
“Rawā ʿan Muslim, wa-rawā ʿanhu Muslim”
He narrated from Muslim, and a person named Muslim narrated from him.
The two may be entirely different transmitters. Complete names and relative generations resolve the ambiguity. The same method applies to repeated names such as Hishām.