auto-completed content comes to end of the line

[yjloong]

Question is writen lsp-issue 1022.
Thanks.

[yjloong]

Hello..

[twlz0ne]

What I want is 'X[start]'. But it gives me 'X[st]art'.

I don't quite understand this. What does the [start]/[st] mean? Would you please tell me what you are typing and in what major mode?

I tried your emacs.d, but it‘s a bit sluggish. Could you provide a minimal configuration?