Vuforia give wrong target name

I use Vuforia 5 version and starter licence key to recognize image targets. I published my app on AppStore and it has worked for 2 weeks. But 4 days ago, I created new xml and dat file from vuforia and my app read the target with wrong name (i think it gives random name-because for same image it can give different names(my xml and dat files include 64 image)). My image name is like 12_02_2014 etc. And my images like each other. I have never see the error like that, and I dont know what I am doing. Did anyone see this error before? I guess it is vuforia's fault. Thanks