This happens when the language is set to "한국어 (대한민국)"

Properly executes when the language is set to "English (US)".

When using

/scoreboard players enable <target> <trigger>

the output should be (as i expected)

<target>에게 <trigger> 트리거를 허가했습니다.

which is

Enabled trigger <trigger> for <target>

in english.

So the way to do this:

/scoreboard objectives add <trigger> trigger

Add a trigger.(Used <trigger> as the name.)

/scoreboard players enable <target> <trigger>

The output is

%2%s 에게 %1$s 트리거를 허가했습니다.

which is

Enabled trigger %1&s for %1%s

in english, whatever <target> and <trigger> is.

Edit 1: Added screenshot.

Command is

/scoreboard objectives add temp trigger
/scoreboard players enable <target> temp

Output is

%2%s 에게 %1$s 트리거를 허가했습니다.

which is same as above.