Hi,
For a simple .emacs file like :
---------------------------------
(add-to-list 'load-path "~/.emacs.d/orglisp")
(require 'org)
(setq org-enforce-todo-dependencies t)
(setq org-agenda-dim-blocked-tasks 'invisible)
(setq org-agenda-files (list "~/org/test.org"))
(setq org-tags-exclude-from-inheritance (quote ("tag")))
---------------------------------

And simple org file like :
--------------------------------
* ordered                               :tag:
  :PROPERTIES:
  :ORDERED:  t
  :END:
** TODO task 1
** TODO task 2
* unordered         :tag:
** TODO task1
---------------------------------

The command "M-x org-agenda m tag" shows both the entries "ordered" and
"unordered". But if "ordered" becomes TODO, like 


--------------------------------
* TODO ordered                               :tag:
  :PROPERTIES:
  :ORDERED:  t
  :END:
** TODO task 1
** TODO task 2
* unordered         :tag:
** TODO task1
---------------------------------

The same command "M-x org-agenda m tag" shows no entry - neither
"ordered" nor "unordered". The "unordered" item should still show up
irrespective of "ordered" being TODO or not.

It appears to be a bug. Is there an explanation / workaround for this?

   I see this issue in 8.2 from stable branch, as well as daily
   snapshot downloaded from http://orgmode.org/org-latest.tar.gz.

thanks