Problem after updating, Forum post crashed : Syntax error or access violation

Hello,

After updating Drupal 7.30 to 7.31, I encounter problem when I go on forum post :

Warning : Illegal offset type in isset or empty dans locale() (ligne 713 dans modules/locale/locale.module).
PDOException : SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'AND s.context = '' AND s.textgroup = 'default'' at line 1: SELECT s.lid, t.translation, s.version FROM {locales_source} s LEFT JOIN {locales_target} t ON s.lid = t.lid AND t.language = :language WHERE s.source = AND s.context = :context AND s.textgroup = 'default'; Array ( [:language] => fr [:context] => ) dans locale() (ligne 720 dans modules/locale/locale.module).

This issue it's only when I open Post of Forum, the rest of website work correctly.
I try to search on issue about this problem, but nothing :(

Have you any idea about the problem ?