$ mkdir -p sub/sub2
$ touch -t 201401010101 sub/file
+ $ touch -t 201401010102 sub
+ $ touch -t 201401010103 sub/sub2
$ _autoenv_stack_entered_add sub
$ _autoenv_stack_entered_add sub/file
$ _autoenv_stack_entered_add sub/sub2
sub sub/file sub/sub2 non-existing
$ echo $_autoenv_stack_entered_mtime
- 0 1388538060 0 0 (glob)
+ 1388538180 1388538060 1388538120 0
Touch the file and re-add it.