The article I read said she used her Harvard law office address in briefs she filed when she represented Travelers and other insurance companies in court over an asbestos-related case. The case lasted for three years, and ended with a Supreme Court win for Travelers. Here's the link to the article I read:
Those were federal cases and it is not considered practicing law in Mass. if she has a license in another state and is admitted to that districts bar. States do not control what happens in federal courts. At least that’s my understanding and why I asked the question. She would need a Mass licence if she did or supervised legal work in Mass. On a case by case basis with the courts prior approval in each case she could practice law in Mass using a license in another state but there would be a record of the filing and court approval. If she supervised students handling a Mass case she would need a Mass license. If she did not have one when she supervised students I wonder what effect it would have on the cases and students law licenses sine the were also practicing law in Mass without a license even if they were misled by their professor.