Legal Question in Real Estate Law in California

That is a minor mistake if it is clear that it is meant to be your name. You could get him to signed a correction to the deed and not file it, so as to not incur the cost, and if in the future there is any problem file it at that time.

Why would a deed from Tom Doe to Jane Doe cause any problem just because it was not to Jane Mary Doe? That makes no sense.

You can ask a title company, preferably one familiar with you or the property, to see whether the supposed error will create any future difficulty for you. The Civil Code (e.g., section 1096) allows someone who has changed their name to sell property under their new name so long as the deed states that they acquired the property under a former name. Maybe the title company can use this technique; i.e., you deed the property to yourself, referencing the defective name as how you acquired title, and the correct name as how you are taking title.