There is a critical mistranslation between English and Japanese interface translations.
When you go to; User Control Panel >> Board preferences >> Edit global settings
The first item in English is "Users can contact me by email: Yes/No"
The first item in Japanese is "メールアドレスを公開する: Yes/No" (meaning "Your email address is publicly disclosed")
And the default setting after the first attempt to log in is "YES". This mistranslation causes a huge security concern among Japanese speakers who set their user interface in Japanese.
If the first item on the User CP functions exactly the same both in English and Japanese, please revise the translation
Incorrect (current): メールアドレスを公開する
↓
Correct (proposed): 他ユーザからのメールを受信する
The same concern is raised by another Japanese-speaking user here.