On vundle's homepage, it documented that it requires filetype to be off in .vimrc:
filetype off " required!
set rtp+=~/.vim/bundle/vundle/
call vundle#rc()
I don't understand why. Since I am encountering problems with editing .coffee and .less files recently after separately-installed related plugins for them (vim-coffee-script and vim-less). My issue on vim-coffee-script