mhchem expressions not rendered correctly

Steps to reproduce:

• Site with MathJax and TeX filters enabled. MathJax before TeX.
• Chemistry notation enabled in MathJax:
  https://docs.moodle.org/en/Chemistry_notation_using_mhchem#via_MathJax
• filter_mathjaxloader | mathjaxconfig:

  MathJax.Hub.Config({

  TeX: { extensions: ["AMSmath.js", "AMSsymbols.js", "mhchem.js", "noErrors.js", "noUndefined.js"] },

  config: ["Accessible.js", "Safe.js"],

  errorSettings: { message: ["!"] },

  skipStartupTypeset: true,

  messageStyle: "none"

  });

• In Moodle-course create a page and add mhchem-expressions.

We have found most mhchem-expressions rendering correctly.
For example:

\(\ce{ \bond{->} }\)

\(\ce{ -> }\)

The following expressions are broken though:

\(\ce{ \bond{<-} }\)

\(\ce{ <- }\)

\(\ce{ <-> }\)

\(\ce{ <=> }\)

\(\ce{ <=>> }\)

\(\ce{ <<=> }\)

\(\ce{ CO2 + C <- 2CO }\)

\(\ce{ CO2 + C <=> 2CO }\)

\(\ce{ H+ + OH- <=>> H2O }\)

Rendering problems seem to occur only in \ce -expressions starting with "<".

We have found that this is a regression caused by MDL-69911.
With TeX-filter disabled or the parameter cleaning introduced by MDL-69911 commented out, the mhchem expressions are rendered correctly.