Does anyone know of any lawsuits where a plan sponsor (e.g., an employer who had retirement plan) sued a third party administrator who had the duty to update the plan for new laws and said third party administrator did not perform that duty?

If the error is discovered before an IRS audit, then why not work out with the adminsitrator who will pay for the IRS and prep fees for a VCP application? It's a slam-dunk correction, and pretty cheap under the simplified procedures of the new EPCRS.

And, read the service agreement with the TPA very carefully. The TPA generally will not take responsibility to update doucments unless they are the TPA's own documents, which usually means it's a prototype that can be updated without the necessity of the employer's signature on the amendment (except big ones, like GUST).