This has happened to me when I do not do a cold start (completely stop the application server, and the restart it)
Well I did just that (restart app server) and it is reading properly from the messagesen.properties file.
So is that a bug or is messagesxy.properties files not hot deployable? The updated contents were visible in the props file in exploded EAR in server/default/deploy.
I was using ant explode the whole time so maybe if I did a ant restart instead it would have worked?