It’s working fine on, 8.4.5 and 8.4.6 xwiki version.
public static String unescape(Object content)
Unescape encoded special XML characters. Only >, < &, " and ' are unescaped, since they are the only ones that affect the resulting markup.
Actually I know what’s wrong. Looks like that module is not embedded by default anymore (because no other module had it as a dependency). Probably since 9.5.
I meant you should use the one corresponding to your version. The only bug here is that the module is not embedded, there was nothing to fix in the module itself so you can safely use the 9.11.2 one.