In Title Update Ver. 5.1, which was released on January 22 at 00:00 UTC, a bug occurred causing Kulve Taroth's resistance parameters to Sleep and Paralysis effects to differ from the originally intended values.
This issue has been addressed.
We've also changed the gameplay system so that points for research objectives accumulate faster if you investigate more actively.
We apologize for not announcing this change in advance and for any inconvenience this may have caused.
Important:
The latest version of MONSTER HUNTER: WORLD is revision number 166660.
You can verify the version number in the top-left corner when you launch the game
in windowed mode.
Keep in mind that you can only match with other players who have the same update
version as you.
For other questions, please visit the official MONSTER HUNTER: WORLD support portal below.
http://www.capcom.com/mhwsupport/