According to the most recent patch note the korean voiceover was fixed but the same bugs are there since release of the game.
That is especially when riding any mount and there is no sound at all.
Please finally fix it, the voiceover with these bugs is really annoying.
Out of curiosity, I checked a cutscene that was previously broken (the Anikka questline cutscene before your fight against Hari), and it still seems to be missing the sound as well. This was one of the cutscenes that was temporarily fixed during the 5/19 - 6/2 period when the DLC was not required. I checked it with the DLC active - not sure if it would be different if the DLC was not loaded, but I won’t be able to test it again until later.