Someone ordered a ketubah and it’s been printed but the wedding has not happened yet. They spelled the chatan’s mother’s name wrong (missing a yud in Shaindel). Is it necessary to change the ketubah?
It’s fine. Remember that a ketubah is, fundamentally, a civil contract (required by halakha)—when there are questions such as these they are assessed based on the rules of Choshen Mishpat contracts, not by some ritual considerations. Thus—the need for names is purely about accurate identification. In principle, it could say the “the chatan-SSN 123-45-6789 said to the kalah-SSN: etc.” Even when it comes to a גט, in principle the first name alone would suffice if the context made it clear whom was the person being referred to (see Shulchan Arukh Even HaEzer 129:9 and AHS 4).
Thus—It is true that if a different name is written—even for the person’s father—it is worse than missing a name and invalid, since it is effectively identifying a different person (who may or may not exist)—see Shulchan Arukh Even HaEzer 129:10.
That being said—in this case, the person has been accurately identified by his name, his father’s name, and location. A missing yud in the mother’s name would not create any doubt at all as to the person being referred to—it will be accurately seen as what it is a misspelling. *The ketubah is totally kosher.*
By the way—even a more serious misspelling might not be a problem, given all the contextual indicators, as mentioned above. But in this case, it is not even a question.