Since I am using English and Korean at the same time, I found it is the issue only found when I am typing Korean.
Take a line of words you are typing.
So you typed through the end of the line and you found there is a typo at the beginning of the line.
So you click the cursor at the beginning where you want to insert a new word.
But the word you newly typed in is not there but going into the end of the line where you left with.
For Example,
많은 시간과 토론을 투자 : you typed one line and want to add a word(는) at the beginning of the line
는많은 시간과 토론을 투자 : you expect
많은 시간과 토론을 투자는 : Result is
I think the reason is when I am typing Korean, the Libreoffice automatically selects the last Korean word typed.
PS: I am using mac so not sure about other OS does the same.