Hi Raych,

Could I know which sample or project template did you use? iOS 9 should have no bug like that base on our internal testing.

Everyone the same exception.

Then I check the source code by ilspy 

if (NSLocale.get_PreferredLanguages().Length > 0){
    this.SystemLanguage = new CultureInfo(NSLocale.get_PreferredLanguages()[0]);
}

 NSLocal.PreferedLanguage[0] is the value "zh-Hans-US" which could not initialize the CultureInfo.

so I think maybe it is a Bug at iOS9.

could it be only occurs in the Chinese language environment?

Hi Raych,

yes it is only occured in chinese language, and i can confirmed and already reported this to our developer under CROS-966

Hope that will helps!
Best regards

Arief