It's lawyer trolling. They get a mailing list ready of upset homeowners and present it to the builder for $$$$, knowing fully well they will settle for $$$ once legal action starts. Yes, your home might get a repair out of the suit - by the lowest bid contractor which adds only more salt to your wound.
If you're in an attached home, these lawsuits are the kiss of death. Some are needed if the builder really screwed up the design, but the number of justifiable lawsuits to simple lawyer trolling has to be a 1 to 10,000 ratio.
If your unit has an issue, check with other owners with the same model first. If it's systemic to the model, then your warranty should handle the work, or a suit might be required. Perhaps some complaints have been made at the HOA meetings no one attends. Give one of those meetings a try just to see what might, or might not be a concern with your home. If there seems to be an over arching issue, and if the HOA can't fix it, then consider hiring a reputable law firm, preferably one that has completed recent work in a similar Irvine community.
My .02c