bufferlines not working properly when working directory changed

[YangchaoYi]

Problems summary

(in shell)
$nvim tmp/file1

(in nvim)
:cd tmp
:CocCommand fzf-preview.BufferLines

Gives error: "[coc.nvim]: Error on "runCommand": ENOENT: no such file or directory, open 'file1'"

Expected

Show lines of file1.

Environment Information

• fzf-preview version (package.json): coc-fzf-preview 2.8.1

• OS: Debian

• Vim/Neovim version: NVIM v0.5.0

Provide a minimal init.vim

call plug#begin('~/.vim/plugged')
Plug 'junegunn/fzf'
Plug 'neoclide/coc.nvim', {'branch': 'release'}
call plug#end()
 
let g:coc_global_extensions = ['coc-fzf-preview']