http://git.cyrusimap.org/cyrus-imapd/commit/?id=6e776956a1a9dfa58eacdd0ddd52644009eac9e5

--- imap/index.c	2009-09-09 01:22:38.000000000 +0000
+++ imap/index.c.oden	2012-03-23 11:44:08.000000000 +0000
@@ -192,6 +192,7 @@ static void index_thread_orderedsubj(uns
 static void index_thread_sort(Thread *root, struct sortcrit *sortcrit);
 static void index_thread_print(Thread *threads, int usinguid);
 static void index_thread_ref(unsigned *msgno_list, int nmsg, int usinguid);
+static void massage_header(char *hdr);
 
 /* NOTE: Make sure these are listed in CAPABILITY_STRING */
 static const struct thread_algorithm thread_algs[] = {
@@ -4118,6 +4119,7 @@ void index_get_ids(MsgData *msgdata, cha
 	/* allocate some space for refs */
 	msgdata->ref = (char **) xmalloc(refsize * sizeof(char *));
 	/* find references */
+	massage_header(buf);
 	refstr = buf;
 	while ((ref = find_msgid(refstr, &refstr)) != NULL) {
 	    /* reallocate space for this msgid if necessary */