[{HVY-E}Jinxx]

Check in your directory where the mission is and look for your mission files.

There should be 2 files, one is a Properties file.
The other is the mission file.
You probably have 2 properties files though. Rename the properties file without the _RU in it (Adding the _RU and you should be able to see your briefing.

Here is an example of what you may be seeing in the directory....

ie. my_mission.mis
my_mission.properties (there may be an additional properties file with _RU in it.)
my_mission_RU.properties

If you are seeing the above, delete the my_mission.properties file.

That should get you seeing the briefing.