I suppose this is compatibility problem with the plugin email-ext.
What occurs is the following :

Mail title : 5 » promotion » Promo1 - Build # 5 - Building!
Mail body : 5 » promotion » Promo1 5

email-ext config title : $DEFAULT_SUBJECT
emain-ext config body : $PROJECT_NAME $BUILD_NUMBER

I tried to set a variable like you did with PROMOTED_URL using the following but I failed (Indeed, PROMOTED_URL is not resolved)

In Promotion.java:67
<code>
@Override
public EnvVars getEnvironment(TaskListener listener) throws IOException, InterruptedException

{ EnvVars e = super.getEnvironment(listener); String rootUrl = Hudson.getInstance().getRootUrl(); e.put("PROMOTED_NAME","nameTest"); e.put("PROMOTED_NUMBER",Integer.toString(targetBuildNumber)); if(rootUrl!=null) e.put("PROMOTED_URL",rootUrl+getTarget().getUrl()); return e; }

</code>