(a) After redistricting or districting, a board shall not adopt new supervisorial district boundaries until after the next federal decennial census, except under the following circumstances:

1. (1) A court orders the board to redistrict.
2. (2) The board is settling a legal claim that its supervisorial district boundaries violate the United States Constitution, the federal Voting Rights Act of 1965 (52 U.S.C. Sec. 10301 et seq.), or this chapter.
3. (3) The boundaries of the county change by the addition or subtraction of territory.
4. (4) The number of supervisors elected by districts or from districts is increased or decreased.
5. (5) An independent redistricting commission is established pursuant to Section 23003 to adopt new supervisorial districts between federal decennial censuses and the districts being replaced were adopted by the board of supervisors.