Goyo enter and exit does not remove tmux

I was using below code to hide tmux while inside Goyo which was working until I recently updated neovim to v0.8.0. Is there a fix for this?
```vim
function! s:goyo_enter()
if executable('tmux') && strlen($TMUX)
silent !tmux set status off
silent !tmux list-panes -F '\#F' | grep -q Z || tmux resize-pane -Z
endif
set noshowmode
set noshowcmd
set scrolloff=999
Limelight
" ...
endfunction
```