Script context initializers provided by installed extensions are ignored

I have a JAR extension that provides a ScriptContextInitializer but it never gets executed after I install the extension at wiki level. If I install the extension at farm / root level then my ScriptContextInitializer is executed only after I restart my XWiki instance.

It looks like the list of ScriptContextInitializer is read only once (from the root component namespace), when the application starts.