38 C.F.R. § 14.808
(b)
(1) If, while testifying in any legal proceeding, VA personnel are asked for expert or opinion testimony concerning official VA information, subjects or activities, which testimony has not been approved in advance in accordance with these regulations, the witness shall:
(d) If VA personnel who are unaware of these regulations provide expert or opinion testimony concerning official VA information, subjects or activities in any legal proceeding, including one mentioned in § 14.802(d) in which the United States is not already represented, without consulting with the responsible VA official, the witness, as soon after testifying as possible, shall inform the responsible VA official of the fact that such testimony was given and provide a summary of the expert or opinion testimony given.
(Authority: 38 U.S.C. 501 (a) and (b); 5 U.S.C. 301)