Admission into country C is governed by the laws of country C. A and B's opinion don't really matter. If it's legal to enter country C with passport B, than they will admit you. The fact that you also have passport of country A and a visa in that passport, doesn't matter. If you present passport B at the border, they will only look at passport B. You CANNOT use the Visa in A in conjunction with passport B.
Example: I have US and German passports and a China Visa in my US passport. If I go to China, I can use my US passport with the China Visa. If I present my German passport, I will be declined entry since this requires a Visa which I don't have.
There are currently 7301190 possible combinations of three different countries. All of which may very well have special rules and provision that make your specific case different from the General Answer.
ADDED since the question has been updated
Does anyone have any recent experience doing this?
Yes, but it REALLY depends on what countries are involved. I can enter Germany with my German or US passport. I can enter Italy with either passport. I can NOT enter the US with my German passport.