I've only had that happen a couple of times, and both times it was because of not enough water. Once when I was away and the irrigation pump failed several days before we got home. The other time was when a pot of some other plant got placed so it was interfering with the sprinkler water getting to the gingers.
They do grow very fast when they're putting up bloom stalks, so lack of water is definitely my best guess. Shower more often?
