supertab insert mapping does not exist after installing supertab about supertab HOT 2 CLOSED

And I use https://github.com/junegunn/vim-plug as the vim plugin manager to install supertab

`" Specify a directory for plugins (for Neovim: ~/.local/share/nvim/plugged)

call plug#begin('~/.vim/plugged')

" Make sure you use single quotes

Plug 'scrooloose/nerdtree'
Plug 'scrooloose/nerdcommenter'
Plug 'kien/rainbow_parentheses.vim'
Plug 'vim-airline/vim-airline'
Plug 'vim-airline/vim-airline-themes'
Plug 'tomasr/molokai'
"Plug 'Shougo/neocomplete.vim'
Plug 'vim-syntastic/syntastic'
Plug 'spf13/vim-autoclose'
Plug 'Raimondi/delimitMate'
Plug 'tpope/vim-surround'
Plug 'majutsushi/tagbar'
Plug 'easymotion/vim-easymotion'
Plug 'rking/ag.vim'
Plug 'thinca/vim-quickrun'
Plug 'junegunn/fzf', { 'dir': '~/.fzf', 'do': './install --all' }
Plug 'AndrewRadev/splitjoin.vim'
"Plug 'SirVer/ultisnips'
Plug 'terryma/vim-multiple-cursors'
Plug 'ctrlpvim/ctrlp.vim'
Plug 'derekwyatt/vim-fswitch'
Plug 'davidhalter/jedi-vim'
Plug 'ervandew/supertab'
"Plug 'fatih/vim-go', { 'do': ':GoUpdateBinaries' }

" Initialize plugin system
call plug#end()`

from supertab.

after building vim from source to version 9.1, this issue disappear but still don't know why.

from supertab.