An example to test this problem:

Evaluate:
(setq org-agenda-custom-commands
      '(("t" "TEST" tags-todo "tag"
         ((org-agenda-sorting-strategy '(deadline-up))))))
then run the view. It will not be sorted properly before the patch, but will be after.

I would also recommend factoring the code that I added out into a separate function (as it also appears almost verbatim in org-agenda-get-todos), but I am not sure the conventions or desire for this.

From c8a7211639d9c138a3b3dcb7e3ce7c85264580f1 Mon Sep 17 00:00:00 2001
From: "Yuri D. Lensky" <ydl@ydl.cm>
Date: Sat, 7 Feb 2015 13:37:46 -0500
Subject: [PATCH] Fix timestamp-based sorting of tags-based entries in agenda

* lisp/org.el (org-scan-tags): Fix agenda org tags scans to properly
  add timestamp property, completely analogously to org-agenda-get-todos.

Before this fix, timestamps were ignored when sorting agenda views of
the 'tags' and 'tags-todo' types.
---
 lisp/org.el | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/lisp/org.el b/lisp/org.el
index a095f8d..54b375e 100755
--- a/lisp/org.el
+++ b/lisp/org.el
@@ -14177,7 +14177,7 @@ headlines matching this string."
          lspos tags tags-list
 	 (tags-alist (list (cons 0 org-file-tags)))
 	 (llast 0) rtn rtn1 level category i txt
-	 todo marker entry priority)
+	 todo marker entry priority ts-date ts-date-type)
     (when (not (or (member action '(agenda sparse-tree)) (functionp action)))
       (setq action (list 'lambda nil action)))
     (save-excursion
@@ -14194,6 +14194,34 @@ headlines matching this string."
 	  (goto-char (setq lspos (match-beginning 0)))
 	  (setq level (org-reduced-level (org-outline-level))
 		category (org-get-category))
+          (when (eq action 'agenda)
+            (setq ts-date (let (ts)
+			(save-match-data
+			  (cond ((org-em 'scheduled-up 'scheduled-down
+					 org-agenda-sorting-strategy-selected)
+				 (setq ts (org-entry-get (point) "SCHEDULED")
+				       ts-date-type " scheduled"))
+				((org-em 'deadline-up 'deadline-down
+					 org-agenda-sorting-strategy-selected)
+				 (setq ts (org-entry-get (point) "DEADLINE")
+				       ts-date-type " deadline"))
+				((org-em 'ts-up 'ts-down
+					 org-agenda-sorting-strategy-selected)
+				 (setq ts (org-entry-get (point) "TIMESTAMP")
+				       ts-date-type " timestamp"))
+				((org-em 'tsia-up 'tsia-down
+					 org-agenda-sorting-strategy-selected)
+				 (setq ts (org-entry-get (point) "TIMESTAMP_IA")
+				       ts-date-type " timestamp_ia"))
+				((org-em 'timestamp-up 'timestamp-down
+					 org-agenda-sorting-strategy-selected)
+				 (setq ts (or (org-entry-get (point) "SCHEDULED")
+					      (org-entry-get (point) "DEADLINE")
+					      (org-entry-get (point) "TIMESTAMP")
+					      (org-entry-get (point) "TIMESTAMP_IA"))
+				       ts-date-type ""))
+				(t (setq ts-date-type "")))
+			  (when ts (ignore-errors (org-time-string-to-absolute ts)))))))
 	  (setq i llast llast level)
 	  ;; remove tag lists from same and sublevels
 	  (while (>= i level)
@@ -14265,7 +14293,9 @@ headlines matching this string."
 	      (org-add-props txt props
 		'org-marker marker 'org-hd-marker marker 'org-category category
 		'todo-state todo
-		'priority priority 'type "tagsmatch")
+                'ts-date ts-date
+		'priority priority
+                'type (concat "tagsmatch" ts-date-type))
 	      (push txt rtn))
 	     ((functionp action)
 	      (setq org-map-continue-from nil)
-- 
1.9.4.msysgit.2