--- gnus-sum.el~	2009-02-05 09:09:28 +0000
+++ gnus-sum.el	2009-05-29 09:45:03 +0000
@@ -9753,10 +9753,8 @@
 				       (list (cdr art-group)))))
 
 	    ;; See whether the article is to be put in the cache.
-	    (let ((marks (if (gnus-group-auto-expirable-p to-group)
-			     gnus-article-mark-lists
-			   (delete '(expirable . expire)
-				   (copy-sequence gnus-article-mark-lists))))
+	    (let ((marks (delete '(expirable . expire)
+				 (copy-sequence gnus-article-mark-lists)))
 		  (to-article (cdr art-group)))
 
 	      ;; Enter the article into the cache in the new group,
@@ -9796,6 +9794,15 @@
 		       to-group (cdar marks) (list to-article) info)))
 		  (setq marks (cdr marks)))
 
+		(when (gnus-group-auto-expirable-p to-group)
+		  ;; Mark this article as expirable
+		  (push 'expire to-marks)
+		  (when (equal to-group gnus-newsgroup-name)
+		    (push to-article gnus-newsgroup-expirable))
+		  ;; Copy the expirable mark to other group.
+		  (gnus-add-marked-articles
+		   to-group 'expire (list to-article) info))
+
 		(gnus-request-set-mark
 		 to-group (list (list (list to-article) 'add to-marks))))