Or Mishnah Megillah end of chapter 1 [the Ein Beins]
Where the Mishnah Digresses a into long list off the topic of the Masechta.
So - Which comes first? The local text or the digression?
Kehatti seems to follows the Traditional explanation - Viz. It is derech agav -suggesting that the local text comes first. And only then, once we discuss ONE exemplary case fitting a certain structure, does the redactor bring down all similar cases. Thus the Mishnah is CREATING this list despite digressing off topic
From a Scientific Study of Mishnah, the converse is a better way of explaining it.
Namely - the Mishnah needs to quote a single relevant case. In order to do so, it quotes [from] a Pre-existing "Article" or "Theme" paper." And once it begins quoting - it proceeds to quote the article in its entirety without trimming it.
So the Mishnah is not adding similar cases as a mnemonic. Rather it is "pulling in" already existing, memorized material, wherein only one case really matches the local subject.
Shloymie: Frankly I do not see a difference or at least a significant difference. Who Cares?
RRW: Indeed the Nafqa Minah is quite subtle. This deals with understanding how the Mishnah [and Talmud!] were redacting tangential pieces.
In a sense - both models include more than is needed in order to preserve these cases.
The subtle difference is the nature of the digression
A. In the Traditional Model it's to teach other cases that have a similar structure although they're really off-topic because we shouldn't forget them.
B. In the Scientific Model the redactor is looking to quote an existing piece "AS IS". Therefore the excursion to side issues is perhaps an unintended consequence of being honest and quoting thoroughly. The digression is not the intended purpose of the quotation at all! Rather the quote is ONLY for local needs and the rest is "pulled in" derech agav to preserve the integrity of the quote - and perhaps also so those cases are not forgotten.
Shloymie: Can you support this with evidence?
RRW: Indeed there is some evidence, though no hard proof.
EG see Arvei P'sachim 101a v'hoamar Abbaye «Master did all [cases] like Rav except [these] 3 . ... #2 - we light from candle to candle [Rashi "MiNer Hanukkah]..."
Now follow Masoret Hashas to Shabbat 21a "Itmar Rav..." re: Ner Hanukkah ALL three cases are quoted, though ONLY the Ner [Hanukkah] case is locally relevant
Contrast this with Torah shebichtav where the Talmud frequently quotes a fragment!
Shloymie: Why do they do that with Tanach?
RRW: Simple! - Tanach is written, go read it. Oral Torah [TSBP] needs to be preserved and quoted fully.
Shloymie: So preserving the memory is important, n'est-ce pas?
RRW Yes, indeedy. Just that the quote already exists and it's not being snipped. Contrast that with the redactor who only at time of redaction begins to assemble a brand new series and thereby creates a digression off-topic.
In the Tradtional model such digressions are therefore lechathcilah being formulated.
While in the Scientific Model, they are more b'di'avad, sticking to the oral text as it was already preserved.
Test both models for yourself by looking at other cases and see which model seems to make more sense.