python autocomplete error: E742: Cannot change value of v:completed_item.is_snippet = 0

[fcying]

vim 8.0 1-1475

when I select the python autocomplete popup menu, it make a error

Error detected while processing function <SNR>24_check_changes[21]..cm#snippet#check_and_inject:
line    8:
E742: Cannot change value of v:completed_item.is_snippet = 0

my vimrc

set nocompatible
set guioptions=
set mouse=n

set runtimepath+=~/.vim/plugged/nvim-completion-manager
set runtimepath+=~/.vim/plugged/vim-hug-neovim-rpc

filetype plugin indent on
syntax enable

[Shougo]

Dup of https://github.com/roxma/nvim-completion-manager/issues/196.