diff --git a/plugin/fugitive.vim b/plugin/fugitive.vim
index 6b64bca..fc5cc4f 100644
--- a/plugin/fugitive.vim
+++ b/plugin/fugitive.vim
@@ -1392,8 +1392,18 @@ call s:command("-bar -nargs=* -complete=customlist,s:EditComplete Gsdiff :execut
 
 augroup fugitive_diff
   autocmd!
-  autocmd BufWinLeave * if &diff && s:diff_window_count() == 2 && getbufvar(+expand('<abuf>'), 'git_dir') !=# '' | call s:diffoff_all(getbufvar(+expand('<abuf>'), 'git_dir')) | endif
-  autocmd BufWinEnter * if &diff && s:diff_window_count() == 1 && getbufvar(+expand('<abuf>'), 'git_dir') !=# '' | call s:diffoff() | endif
+  autocmd BufWinLeave *
+        \ if getwinvar(bufwinnr(+expand('<abuf>')), '&diff') &&
+        \     s:diff_window_count() == 2 &&
+        \     !empty(getbufvar(+expand('<abuf>'), 'git_dir')) |
+        \   call s:diffoff_all(getbufvar(+expand('<abuf>'), 'git_dir')) |
+        \ endif
+  autocmd BufWinEnter *
+        \ if getwinvar(bufwinnr(+expand('<abuf>')), '&diff') &&
+        \     s:diff_window_count() == 1 &&
+        \     !empty(getbufvar(+expand('<abuf>'), 'git_dir')) |
+        \   call s:diffoff() |
+        \ endif
 augroup END
 
 function! s:diff_window_count() abort