The Rambam ['איסורי ביאה י"ג ט] writes that the Gemara we quoted [Yevamos 45b] which says that when the woman immersed herself for Niddah [or a man immersed for his seminal emission] that means she is a giyores, means that this PROVES that she had converted earlier because she is acting like a Jewess but not that the טבילה constitutes an act of conversion now [as one might read the Gemara simply]. Thereby the Magid Mishna says that we can answer the question of the Rif from the Gemara that says that you need 3 judges present at the conversion. In fact 3 ARE needed and that is מעכב as the Rambam implies there in 'הלכה ז and this sugya is not talking about the act of conversion but rather her טבילה is just an indication that she is already Jewish. The M"M quotes the Rif and notes that his words are close to the Rambam's. So wrote the Meiri according to the Rif as did the Bach [268] and this is implicit from the language of the Rif:
"דאי לאו גיורא לא הוה טבל לשם קריו".
If not for the geirus he would not have immersed himself for his seminal emission.
That sounds like this was not a מעשה גירות but merely an indication that he was already part of the tribe.
On the other hand 👆 after he resolved the question from the Gemara that requires three, why did the Rif have to add that Rav Yochanan only required 3 judges לכתחילה but not בדיעבד?? [And then the Ramban and others said that three judges ARE מעכב so what the Rif means is that 3 are not מעכב for מילה and טבילה but for קבלת המצוות three judges ARE מעכב. See 'חמדת שלמה יו"ד סי' כ"ט ול] Once the question is resolved, why make unnecessary distinctions??
So one one hand the Rif implies as understood by the Ramban and other Rishonim [to distinguish about the number of judges needed between לכתחילה and בדיעבד]. On the other - he seems to write like the Rambam that the Gemara is not talking about the actual מעשה גירות but about the proof that such a מעשה had already taken place.
STIRRRRAAAA!!!!
