If you have several aliases for the one place, and will request alias from drupal_lookup_path(), it will return first occured alias in database.

From: damz <damz@dev.local.local>


---

 path.inc              |    4 ++--
 system/system.install |   11 +++++++----
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git includes/path.inc includes/path.inc
index 72dbb9b..4c08b9a 100644
--- includes/path.inc
+++ includes/path.inc
@@ -66,7 +66,7 @@ function drupal_lookup_path($action, $path = '', $path_language = '') {
         return $map[$path_language][$path];
       }
       // Get the most fitting result falling back with alias without language
-      $alias = db_query("SELECT dst FROM {url_alias} WHERE src = :src AND language IN(:language, '') ORDER BY language DESC", array(
+      $alias = db_query("SELECT dst FROM {url_alias} WHERE src = :src AND language IN(:language, '') ORDER BY language DESC, pid DESC", array(
         ':src' => $path,
         ':language' => $path_language))
         ->fetchField();
@@ -80,7 +80,7 @@ function drupal_lookup_path($action, $path = '', $path_language = '') {
       $src = '';
       if (!isset($map[$path_language]) || !($src = array_search($path, $map[$path_language]))) {
         // Get the most fitting result falling back with alias without language
-        if ($src = db_query("SELECT src FROM {url_alias} WHERE dst = :dst AND language IN(:language, '') ORDER BY language DESC", array(
+        if ($src = db_query("SELECT src FROM {url_alias} WHERE dst = :dst AND language IN(:language, '') ORDER BY language DESC, pid DESC", array(
                      ':dst' => $path,
                      ':language' => $path_language))
             ->fetchField()) {
diff --git modules/system/system.install modules/system/system.install
index 97cc5f2..387a215 100644
--- modules/system/system.install
+++ modules/system/system.install
@@ -1254,11 +1254,11 @@ function system_schema() {
       ),
     ),
     'unique keys' => array(
-      'dst_language' => array('dst', 'language'),
+      'dst_language_pid' => array('dst', 'language', 'pid'),
     ),
     'primary key' => array('pid'),
     'indexes' => array(
-      'src_language' => array('src', 'language'),
+      'src_language_pid' => array('src', 'language', 'pid'),
     ),
   );
 
@@ -3203,11 +3203,14 @@ function system_update_7017() {
 }
 
 /**
- * Replace src index on the {url_alias} table with src, language.
+ * Replace src index on the {url_alias} table with src, language and add pid
+ * column to {url_alias} indexes.
  */
 function system_update_7018() {
   $ret = array();
-  db_add_index($ret, 'url_alias', 'src_language', array('src', 'language'));
+  db_drop_index($ret, 'url_alias', 'dst_language');
+  db_add_index($ret, 'url_alias', 'dst_language_pid', array('dst', 'language', 'pid'));
+  db_add_index($ret, 'url_alias', 'src_language_pid', array('src', 'language', 'pid'));
   db_drop_index($ret, 'url_alias', 'src');
 
   return $ret;