Steps to reproduce:

1. Login Zabbix Web frontend and change to ja_JP or ru_RU.
2. Access to [Configuration]>[Actions]>[Create action]->[Operations].
3. Click on [Add] button of Operations. See the [Add] button at dialog footer.
4. Add any Operation setting. 
5. Click [edit] button to modify Operation added in step 4. See the [Update] button at dialog footer.

Result:
See 01_, 02_ screenshots. In both languages, [Add] button element is not translated.
See 03_, 04_, screenshots. In both languages, [Update] button element is not translated.
Expected:
[Add] and [Update] buttons are translated.