Attempted Incorporation. Notwithstanding any provision herein to the contrary, in the event that an election is called pursuant to applicable law in connection with a bona fide petition for incorporation of a municipality that includes a substantial portion of the District, the City shall be entitled to immediately annex that portion of the District which is proposed to be incorporated; provided, however, the City acknowledges the requirements of 43.071(b) and agrees not to annex for full purposes less than all of the District.