Steps to Reproduce:
- Enable VisualEditor formulae editing at Special:Preferences#mw-prefsection-betafeatures.
- Change math-related preferences to:
- Leave it as TeX (for text browsers) (radio button; it's off by default)
- MathJax (experimental; best for most browsers) (tick box; it's off by default)
- Open a page like [[:w:Torque]] in VisualEditor.
- Select a math formula from the page.
- Open the math editing tool.
- Change some thing in the formula (e.g., replace "alpha" with "beta").
- Look at the mess in the new version of the math formula (the one on the page, not the TeX code in the editing tool).
See screenshots here: