In the Ninth Circuit, a defendant does not waive its objection to personal jurisdiction if, after litigating that issue to an adverse decision on a motion to dismiss, the defendant then defends on the merits and alleges a counterclaim against the plaintiff.  Merely alleging lack of personal jurisdiction as an affirmative defense in an answer isn’t enough to avoid waiver, but prosecuting a motion to dismiss to an adverse decision is.

Ninth Circuit Court of Appeals (Smith, N.R.); September 7, 2018; 2018 U.S. App. LEXIS 25426