You’ve got a really good point. What’s the saying, “Never attribute to malice what you can attribute to stupidity?” It is definitely plausible that the previous owners did not realize there was a problem, painted to make it look nice to sell, and did not intend to deceive OP. For that matter, I suppose it’s possible this happened with the owner before them, and they never even knew. OP should definitely investigate this from a legal aspect, but if they don’t get satisfaction they can’t let this eat at them for the next 30 years.

I really appreciate your perspective on this.