I have the same error when tags is enabled.
Illuminate \ Database \ QueryException (01000)
SQLSTATE[01000]: Warning: 1265 Data truncated for column 'last_time' at row 1 (SQL: update `tags` set `last_time` = 2015-08-31 06:12:15, `last_discussion_id` = 1 where `id` = 1)
/Users/liujin/Sites/flarum/flarum/vendor/illuminate/database/Connection.php
$result = $callback($this, $query, $bindings);
}
// If an exception occurs when attempting to run a query, we'll format the error
// message to include the bindings with SQL, which will make this exception a
// lot more helpful to the developer instead of just the database's errors.
catch (Exception $e) {
throw new QueryException(
$query, $this->prepareBindings($bindings), $e
);
