We are not facing issue with the labels and menu items.
Issue is with only "C" alphabet. It seems Japanese language pack is overriding the field value record value. Would like to know the character used for "C" in Japanese language pack.
In the field value record we created in our application Ruleset A, we have put Japanese character for "C", which at run time is being overridden by Ruleset A_ja (as operator default locale is set to ja_JP).