MathJax 4 warning and TeX conversion failure

Issue Summary

In trying out v4, I get a warning "MathJax: Invalid option "enableAssisitiveMml" (no default value)."

I have

    MathJax = {
      loader: {load: ['input/tex', 'input/asciimath']},
      options: {
        enableMenu: false, // interferes with navigation
        enableAssistiveMml: true,
      }
    };

I didn't see anything in https://github.com/mathjax/MathJax-src/releases/tag/4.0.0-alpha.1 about a change regarding that option. The application doesn't run.

After fixing the above by commenting out the line, the application (see #2937) doesn't run. The error in the console is:

(index):30 MathJax conversion error:  Error: MathJax retry
    at t.retryAfter (tex-mml-chtml.js:1:768405)
    at a.enrich (tex-mml-chtml.js:1:43964)
    at Object.renderMath (tex-mml-chtml.js:1:82401)
    at t.renderConvert (tex-mml-chtml.js:1:83214)
    at e.convert (tex-mml-chtml.js:1:92292)
    at e.convert (tex-mml-chtml.js:1:86327)
    at t.MathJax.<computed> [as tex2mml] (tex-mml-chtml.js:1:70018)
    at ConvertToMathML ((index):25:28)
    at imports.wbg.__wbg_ConvertToMathML_1ba3a1bdd5856d88 (index-efa97dbedd7f5bfc.js:317:21)
    at <math_cat_demo::Model as yew::html::component::Component>::update::h0af6f1cc7b48c509 (index-efa97dbedd7f5bfc_bg.wasm:0x556ff)

The input is x = {-b \pm \sqrt{b^2-4ac} \over 2a} and the JS being run is

    function ConvertToMathML(math_str, math_format) {
      MathJax.startup.defaultReady();
      let options = {display: true};
      let mathml;
      try {
        if (math_format == 'ASCIIMath') {
          mathml = MathJax.asciimath2mml(math_str, options);
        } else if (math_format == 'TeX') {
          mathml = MathJax.tex2mml(math_str, options);
        } else {  // should be "MathML"
          mathml = MathJax.mathml2mml(math_str, options);
        };
      } catch (e) {
        console.error("MathJax conversion error: ", e);
        mathml = "<math><merror>MathJax conversion error</merror></math>"
      }
      console.log("ConvertToMathML:\n" + mathml.toString());
      return mathml;
    }

Environment

This is on Windows 10.
In Firefox, I only see the warning. In Chrome, I get the above error:

Start with the MathJax configuration and the ConvertToMathML function shown in the report, then reproduce the warning and TeX conversion failure in Chrome and Firefox using the provided input. Check the v4 alpha behavior referenced in the release notes and issue #2937; done means the invalid-option warning is resolved and the TeX conversion succeeds.