The patch seems to have broken(reverted) the way personal reward is obtained for guild rush.
https://forum-en.gw2archive.eu/forum/info/updates/Game-Update-Notes-November-17-2015/5768190
Players will now earn personal rewards on guild rushes as soon as they cross the finish line.
Is how it is supposed to be but right now it is behaving as the old behavior which requires completing the rush event (getting 15/15 completions) to get the personal reward.