mathjax 4 issue

[hjy1210]

1. overline issue
   In MathJax3 $\overline{GI}$ produce following mathml

<math xmlns='http://www.w3.org/1998/Math/MathML'>
 <mover>
  <mrow>
    <mi>G</mi>
    <mo>&#x2063;</mo>
    <mi>I</mi>
  </mrow>
  <mo accent='true'>¯</mo>
 </mover>
</math>

which read as line segment cap g cap i math.

In MathJax4 $\overline{GI}$ produce following mathml

<math xmlns='http://www.w3.org/1998/Math/MathML'>
 <mover>
  <mrow>
    <mi>G</mi>
    <mo>&#x2061;</mo>
    <mi>I</mi>
  </mrow>
  <mo accent='true'>¯</mo>
 </mover>
</math>

which read as quantity cap g of cap i with line above math.

2. mhchem water issue
   In mathJax3 $\ce{H2O}$ produce following mathml

<math xmlns='http://www.w3.org/1998/Math/MathML'>
 <mrow>
  <mmultiscripts>
    <mi mathvariant='normal'>H</mi>
    <mn>2</mn>
    <none></none>
  </mmultiscripts>
  <mo>&#x2063;</mo>
  <mi mathvariant='normal'>O</mi>
 </mrow>
</math>

which read as cap h sub 2 cap o math.

In mathJax4 $\ce{H2O}$ produce following mathml

<math xmlns='http://www.w3.org/1998/Math/MathML'>
 <mrow>
  <mi mathvariant='normal'>H</mi>
  <mo>&#x2061;</mo>
  <mrow>
    <mmultiscripts>
      <mo>&#x2062;</mo>
      <mprescripts></mprescripts>
      <mn>2</mn>
      <none></none>
    </mmultiscripts>
    <mi mathvariant='normal'>O</mi>
  </mrow>
 </mrow>
</math

which read as cap h of pre sub 2 cap o math.

In both cases, output of mathjax 3 is what MathCAT expected.
In both cases ⁡ appeared in MathJax4.

What is MathCAT's solution? Can these issue be solved from MathCAT side?