A marfu` narration is attributed to the Prophet; a mawquf narration stops at a Companion. If a weak transmitter raises a report while more dependable transmitters preserve it as Companion-level speech, the dispute concerns the very attribution of the statement, not merely length of wording.
A Companion's own report and an established attribution to the Prophet are different evidentiary levels. Where the weak raised form contradicts stronger mawquf routes, classifying the former as munkar is a judgment about transmission.
Qualification: this does not imply that every similar prophetic narration is invalid. The classification concerns the particular text, chains, and competing versions under study.