This seems like a pretty big screw-up.
Plaintiff makes a CCP 998 offer for $1 million, it doesn't get accepted, and at trial plaintiff wins $3.9 million. Among other things (e.g., expert witness fees), that means plaintiff is entitled to a boatload of prejudgment interest; neither the opinion nor the briefs exactly how much, but it's a fair piece of time at 10%/year on $2.9 million (i.e., $3.9 million minus $1 million). The trial court awards that amount.
The Court of Appeal reverses, holding that the 998 offer wasn't effective because it didn't have a place where the defendant could sign (or any instructions on how to accept the offer).
It's pretty easy to draft an effective 998 offer; you can even look at samples online. That simple mistake here costs the plaintiff a ton of money.
Not exactly the best look for plaintiff's counsel. Or happy news for its malpractice carrier.
P.S. - The web site for plaintiff's counsel is a bit too flashy for my tastes. It's like something that you'd see on (bad) late night television.