When editing the mw:Extension/Math nodes, the edits are not saved. Restoring such a translation loses the edits.
For example, try a translation from en:Crystal structure to Spanish. Translate the mathematical formula under "Interplanar spacing" title using the Math editor. Save and restore. See that your changes are lost.
The mw:Extension/Math does not trigger the events that are required for CX to trigger a save. The missing events also cause some section alignment issues as noted in T202180.