An equals sign (=) contained in a URL within a Crucible comment does not offer a proper, i.e. while http://caniuse.com/#feat=es5 renders properly, the link shown when hovering it is caniuse.com/#feat.

Workaround
URL encode the equals sign (%3d). In the example above, the URL to be posted on the comment would be http://caniuse.com/#feat%3des5