h,.. could you re-check using final version? I used the same code and getting only one message.
Sorry for such a late reply. I had no idea what was going wrong until now. I am pretty sure, that the cause was due to setting javax.faces.SEPARATOR_CHAR to underscore ("_"), instead of default colon (":"). When I reset it to colon, it started to work correctly.
So... anybody be careful about it!
P.S. RF 4.0.0.Final does not resolve the issue.