Correct use of reselect createSelector and memoizeOptions

I am working on building a custom selector using the createSelector from reselect. The input selectors will be returning data that will fail the default === comparison. To make sure I understood the behavior I am building some fundamental tests that return arrays from the input selectors.

I am expecting the results will be recomputed with every call to the selector, but that is not what I am seeing. The function is not recomputing even when I had memoizeOptions that ensure the input selector comparisons return false.

I am not sure what I am doing wrong or what fundamental mistake I am making in this test that is tripping me up. I would appreciate any help getting this figured out.

I am using Jest v27.4.7, node v15.12.0, with reselect 4.1.6 on Linux.

import {test, expect} from '@jest/globals';
import { createSelector } from "reselect";

test("createSelector:array", async () => {

    const a: number[] = [1, 2, 3, 4, 5];
    const b: string[] = ["a", "b", "c", "d", "e"];
    const state0: { a: number[], b: string[] } = { a, b };

    // https://github.com/reduxjs/reselect#reselect
    //    > createSelector determines if the value returned by an input-selector has changed between calls
    //    > using reference equality (===). Inputs to selectors created with createSelector should be immutable.
    const select = createSelector(
        (state, index: number): number[] => state.a.slice(0, index),
        (state, index: number): string[] => state.b.slice(0, index),
        (a_in: number[], b_in: string[]): (number | string)[] => [...a_in, ...b_in],
        { memoizeOptions: { equalityCheck: (a, b) => { console.debug("equalityCheck", a, b); return false }, resultEqualityCheck: (a, b) => { console.debug("resultEqualityCheck", a, b); return false } } } // THESE DO NOTHING, WHY?
    );

    let out = select(state0, 2);
    expect(out).toEqual([1, 2, "a", "b"]);
    expect(select.recomputations()).toEqual(1);

    out = select(state0, 2);
    expect(out).toEqual([1, 2, "a", "b"]);
    expect(select.recomputations()).toEqual(2); // THIS IS 1, WHY?
});