Steps to replicate the issue (include links if applicable):
Mathoid:<br> <math chem forcemathmode=mathml>\ce{\overbrace{\ce{H2O}}}</math> MathJax-client SVG:<br> <math chem forcemathmode=mathjax>\ce{\overbrace{\ce{H2O}}}</math>
What happens?:
Rendering shows raw mathml syntax instead of the formula:
Other information (browser name/version, screenshots, etc.):
Simplified example from https://en.wikipedia.org/w/index.php?title=Proton_exchange_membrane_electrolysis&oldid=1368994456

