The discussion that y not refer to is at, “Difference between Magga and Phala Citta.”
It is those who are not knowledgeable in Abhidhamma that run into this issue. Then they say that Abhidhamma is not consistent with the Sutta Piṭaka.
– EVERYTHING in the three Piṭaka (Sutta, Vinaya, Abhidhamma) are fully self-consistent.
– I looked at MN 142 and SN 55.24 that the Thero referred to in the discourse. There is no inconsistency with Abhidhamma.
There are four magga phala. Each phala citta arises right after the magga citta.
– A magga citta DOES NOT mean the Anugami stage.
– A “magga anugami” has not had a “magga citta” yet.
– The relevant citta vithi is discussed in the subsection “Citta Vīthi for Attainment of Magga Phala” toward the end of the post, “Citta Vithi – Processing of Sense Inputs”
– when someone cultivates the Path, it COULD take a lot of time to go through Parikamma (P), Upacara (U), Anuloma (A), Gotrabu (G) stages. For example, one may get to the Parikamma (P) stage after some months, and then to the Upacara (U) after more time.
– Then one may get to the Gotrabu (G) stage, and that is when one becomes a Sotapanna Anugami. That is called “change lineage” to become an Ariya or a Noble Person. This is what most people do not realize. A Sotapanna Anugami is an Ariya.
– After more time (depending on the person), one WILL get to the magga citta. That magga citta is INVARIABLY followed by the phala citta. There is no “gap” between the magga citta and the phala citta. A Sotapanna Anugami becomes a Sotapanna at that point.
– Until one reaches the Gotrabu (G) stage, the process is reversible.
– But once the Gotrabu (G) stage is attained, one is an Ariya and WILL NOT go back.
The process is similar for the higher stages of magga phala. Once one becomes a Sotapanna, that does not mean he/she is a Sakadagami Anugami. He/she has to start working on getting to the next stage to become a Sakadagami Anugami.
Also, see, “Sōtapanna Anugāmi – No More Births in the Apāyās.”