Wine and Oil (Eruvin 71a)

Rav explains that the beginning of the mishna is talking about when the wine is in one utensil but if the wine is in two utensils it would not be good. Rava then tries to bring a proof that must be true from our Mishna and Abaye says that Rava's proof is no good. I think that the simple understanding of the gemara (especially when considering that Rava and Abaye were from the same generation - a few years later than Rav) is that the only machlokes is if the mishna can be used as a proof but Abaye does not intend to argue on Rav's statement. The Ritva though actually quotes it as two opinions and according to some Abaye is actually arguing on Rav.

Then on amud beis, Rav Yosef explains that the machlokes between R' Shimon and the Chachamim is if wine and oil mix or not. This makes it seem that he's definitely arguing with Rav and that's how the Maharsha explains it. Rav says the machlokes has nothing to do with the substance but the only thing that matters is if it's one utensil or two and Rav Yosef seems to say that the only thing that matters is the substance.

The Sfas Emes (it's very short but this is at least how I understand it) says that he disagrees with the Maharsha and he says that it could be that Rav Yosef and Rav agree. According to them the Chachamim hold that if it's wine then it depends if it's in one utensil or two but if it's wine and oil then it's no good even if they're both in one utensil. That also seems to be how the Ritva understands it.