JSanity strips out text-decoration on Chrome 57+ and Firefox 36+
After those versions, the browsers switched text-decoration to be a shorthand for:
- text-decoration-line
- text-decoration-style
- text-decoration-color
- text-decoration-thickness
The sanitizer works by reading the computed values, so it sees these new properties, doesn't recognize them, and sets them to null.
Depending on the browser, this affects the shorthand property text-decoration differently, but in effect, it removes the property.
See also: https://developer.mozilla.org/en-US/docs/Web/CSS/text-decoration