which in turn prompted the 3rd amended infringement contentions. see (a) below.

3-6. Amendment to Contentions

Amendment of the Infringement Contentions or the Invalidity Contentions may be made only by order of the Court upon a timely showing of good cause. Non-exhaustive examples of circumstances that may, absent undue prejudice to the non-moving party, support a finding of good cause include:

(a) A claim construction by the Court different from that proposed by the party seeking amendment;

(b) Recent discovery of material, prior art despite earlier diligent search; and

(c) Recent discovery of nonpublic information about the Accused Instrumentality which was not discovered, despite diligent efforts, before the service of the Infringement Contentions.

The duty to supplement discovery responses does not excuse the need to obtain leave of court to amend contentions.

See patent local rules

http://www.cand.uscourts.gov/localrules