Family Code § 5700.314

(a) Participation by a petitioner in a proceeding under this part before a responding tribunal, whether in person, by private attorney, or through services provided by the support enforcement agency, does not confer personal jurisdiction over the petitioner in another proceeding.

(b) A petitioner is not amenable to service of civil process while physically present in this state to participate in a proceeding under this part.

(c) The immunity granted by this section does not extend to civil litigation based on acts unrelated to a proceeding under this part committed by a party while physically present in this state to participate in the proceeding.