Default Scope With Relation Problem

Background:
1. Agent model
I have an Agent model, which has a default scope implemented like

'condition'=>'t.agent_id='.Yii::app()->user->join

where join is a session variable.
Note: I have disambiguated the agent_id, because other tables do also have this column. Otherwise exceptions occur on relational queries.

2. AgentRequest model
This is another model to store agent requests, it has following relationship with Agent

'agent' => array(self::BELONGS_TO, 'Agent', 'agent_id'),

Problem
Following exception occurs when trying to access the 'agent' relation. For example i am trying to access $model->agent in AgentReqest view _form.php.

CDbCommand failed to execute the SQL statement: SQLSTATE[42S22]: Column not found: 1054 Unknown column 't.agent_id' in 'where clause'. The SQL statement executed was: SELECT `agent`.`agent_id` AS `t1_c0`, `agent`.`first_name` AS `t1_c1`, `agent`.`last_name` AS `t1_c2` ......(and other fields)
FROM `mts_agent` `agent`
WHERE (t.agent_id=4 or parent_id=4) AND (`agent`.`agent_id`=:ypl0). Bound with :ypl0=NULL

If i change

'agent' => array(self::BELONGS_TO, 'Agent', 'agent_id'),

To

'agent' => array(self::BELONGS_TO, 'AgentScopeLess', 'agent_id'),

Where AgentScopeLess is Agent model without default scope.

Then it is working fine, but i want to make it functional with default scope, as it has some sense as per my logic.

Waiting for your reply please.

Shahzad