rvm complain of "PATH is not properly set up"

rvm complains

Warning! PATH is not properly set up, 
'/home/me/.rvm/gems/ruby-2.1.1/bin' is not at first place, usually this is caused by shell initialization files - check them for 'PATH=...' entries, it might also help to re-add RVM to your dotfiles: 'rvm get stable --auto-dotfiles', to fix temporarily in this shell session run: 'rvm use ruby-2.1.1'.

whenever rvm(v1.25.21) is called, though rvm works perfectly as expected.

By tracing back the message, I figured out the problem lies in

$HOME/.rvm/script/cli

rvm()
{
   ...
   __rvm_path_match_gem_home_check;
   ...
}

$HOME/.rvm/script/functions/cli

__rvm_path_match_gem_home_check_warning()
{
  rvm_warn "\
  Warning! PATH is not properly set up, '$GEM_HOME/bin' $1, usually this is caused by shell initialization files - check them for 'PATH=...' entries, it might also help to re-add RVM to your dotfiles: 'rvm get stable --auto-dotfiles',to fix temporarily in this shell session run: 'rvm use ${GEM_HOME##*/}'."
}

__rvm_path_match_gem_home_check()
{
  (( ${rvm_silence_path_mismatch_check_flag:-0} == 0 )) || return 0
  [[ -n "${GEM_HOME:-}" ]] || return 0
  case "$PATH:" in
    ($GEM_HOME/bin:*) true ;; # all fine here
    (*:$GEM_HOME/bin:*)
      __rvm_path_match_gem_home_check_warning "is not at first place"
      ;;
    (*)
      __rvm_path_match_gem_home_check_warning "is not available"
      ;;
  esac
}

Now it is clear.
This line is the trigger.
($GEM_HOME/bin:*) true ;; # all fine here
Whenever the $PATH does not START WITH $GEM_HOME/bin, the error message is fired.

So...the solution, I now source $HOME/.rvm/script/rvm after any other scripts finish modifying the path.