I ordered trays of ready green beans to serve at a simcha, they just had to be heated up. When served, they were perfectly edible but slightly under-cooked and crunchy. I contacted the caterer and he told me: this is the 21st century and this is the way the green beans are served. Had I known this in advance I probably would have asked him to cook it more and make them softer, the way I am used too, but I’m not too bothered with the way it turned out. Wandering if there is any שאלה of מקח טעות?
More importantly, I am now wondering, what if I would have these green beans on my hotplate for Shabbos? If the norm has indeed changed, does this mean that they can be considered מבושל כל צרכו at an earlier stage, and חזרה now be permitted, even though I would normally cook them more before serving them?
Assuming that what the caterer said is true, then it would not be a מקח טעות, since he didn’t give you a defective or damaged item. Regarding Shabbos what you are saying sounds correct. If it is cooked to the degree that one would serve it to his guest then it is considered נתבשל כל צרכו.
Have a good Shabbos