diff --git a/core/dbobjectsearch.class.php b/core/dbobjectsearch.class.php
index 0dba2f23c..c2700ff81 100644
--- a/core/dbobjectsearch.class.php
+++ b/core/dbobjectsearch.class.php
@@ -340,7 +340,6 @@ class DBObjectSearch extends DBSearch
 		$oTranslated = $oFilter->GetCriteria()->Translate($aTranslation, false, false /* leave unresolved fields */);
 		$this->AddConditionExpression($oTranslated);
 		$this->m_aParams = array_merge($this->m_aParams, $oFilter->m_aParams);
-		$oFilter->ResetCondition();
 	}
 
 	public function RenameParam($sOldName, $sNewName)
@@ -866,8 +865,10 @@ class DBObjectSearch extends DBSearch
 	 * @throws CoreException
 	 * @throws CoreWarning
 	 */
-	public function AddCondition_PointingTo(DBObjectSearch $oFilter, $sExtKeyAttCode, $iOperatorCode = TREE_OPERATOR_EQUALS, &$aRealiasingMap = null)
+	public function AddCondition_PointingTo(DBObjectSearch $oOrigFilter, $sExtKeyAttCode, $iOperatorCode = TREE_OPERATOR_EQUALS, &$aRealiasingMap = null)
 	{
+		/** @var \DBObjectSearch $oFilter */
+		$oFilter = $oOrigFilter->DeepClone();
 		if (!MetaModel::IsValidKeyAttCode($this->GetClass(), $sExtKeyAttCode))
 		{
 			throw new CoreWarning("The attribute code '$sExtKeyAttCode' is not an external key of the class '{$this->GetClass()}'");
@@ -958,8 +959,11 @@ class DBObjectSearch extends DBSearch
 	 * @return void
 	 * @throws \CoreException
 	 */
-	public function AddCondition_ReferencedBy(DBObjectSearch $oFilter, $sForeignExtKeyAttCode, $iOperatorCode = TREE_OPERATOR_EQUALS, &$aRealiasingMap = null)
+	public function AddCondition_ReferencedBy(DBObjectSearch $oOrigFilter, $sForeignExtKeyAttCode, $iOperatorCode = TREE_OPERATOR_EQUALS, &$aRealiasingMap = null)
 	{
+		/** @var \DBObjectSearch $oFilter */
+		$oFilter = $oOrigFilter->DeepClone();
+
 		$sForeignClass = $oFilter->GetClass();
 		if (!MetaModel::IsValidKeyAttCode($sForeignClass, $sForeignExtKeyAttCode))
 		{
diff --git a/test/core/DBSearchAddCondition_ReferencedByTest.php b/test/core/DBSearchAddCondition_ReferencedByTest.php
new file mode 100644
index 000000000..28a7057eb
--- /dev/null
+++ b/test/core/DBSearchAddCondition_ReferencedByTest.php
@@ -0,0 +1,80 @@
+<?php
+
+namespace Combodo\iTop\Test\UnitTest\Core;
+
+use CMDBSource;
+use Combodo\iTop\Test\UnitTest\ItopDataTestCase;
+use DBSearch;
+
+/**
+ * Class DBSearchIntersectTest
+ *
+ * @package Combodo\iTop\Test\UnitTest\Core
+ *
+ * @runTestsInSeparateProcesses
+ * @preserveGlobalState disabled
+ * @backupGlobals disabled
+ */
+class DBSearchAddCondition_ReferencedByTest extends ItopDataTestCase {
+
+	protected function setUp()
+	{
+		parent::setUp();
+		require_once(APPROOT.'application/startup.inc.php');
+	}
+
+	/**
+	 * @dataProvider AddCondition_ReferencedByProvider
+	 *
+	 * @param $sLeftSelect
+	 * @param $sRightSelect
+	 * @param $sParentAtt
+	 * @param $sResult
+	 *
+	 * @throws \CoreException
+	 * @throws \CoreWarning
+	 * @throws \MissingQueryArgument
+	 * @throws \MySQLException
+	 * @throws \OQLException
+	 */
+	public function testAddCondition_ReferencedBy($sLeftSelect, $sRightSelect, $sParentAtt, $sResult)
+	{
+		$oLeftSearch = DBSearch::FromOQL($sLeftSelect);
+		$oRightSearch = DBSearch::FromOQL($sRightSelect);
+
+		$oResultSearch = $oLeftSearch->Join($oRightSearch,
+			DBSearch::JOIN_REFERENCED_BY, $sParentAtt,
+			TREE_OPERATOR_EQUALS, $aRealiasingMap);
+
+		CMDBSource::TestQuery($oResultSearch->MakeSelectQuery());
+		$this->assertEquals($sResult, $oResultSearch->ToOQL());
+	}
+
+	public function AddCondition_ReferencedByProvider()
+	{
+		// Breakpoint in BrowseBrickController::DisplayAction()
+		// $aLevelsProperties[$aLevelsPropertiesKeys[$i]]['search'] = $aLevelsProperties[$aLevelsPropertiesKeys[$i]]['search']->Join($aLevelsProperties[$aLevelsPropertiesKeys[$i + 1]]['search'],
+		//							DBSearch::JOIN_REFERENCED_BY, $aLevelsProperties[$aLevelsPropertiesKeys[$i + 1]]['parent_att'],
+		//							TREE_OPERATOR_EQUALS, $aRealiasingMap);
+		return [
+			'Bug 3176' => [
+				'left' => "SELECT `L-1-1` FROM Service AS `L-1-1` JOIN lnkCustomerContractToService AS `l1` ON `l1`.service_id = `L-1-1`.id JOIN CustomerContract AS `cc` ON `l1`.customercontract_id = `cc`.id WHERE ((`cc`.`org_id` = 2) AND (`L-1-1`.`status` != 'obsolete'))UNION SELECT `L-1-1` FROM Service AS `L-1-1` JOIN lnkCustomerContractToService AS `l11` ON `l11`.service_id = `L-1-1`.id JOIN CustomerContract AS `cc1` ON `l11`.customercontract_id = `cc1`.id JOIN Organization AS `child` ON `cc1`.org_id = `child`.id JOIN Organization AS `root` ON `child`.parent_id BELOW `root`.id WHERE ((`root`.`id` = 2) AND (`L-1-1`.`status` != 'obsolete'))",
+				'right' => "SELECT `L-1-1-1` FROM ServiceSubcategory AS `L-1-1-1` WHERE (`L-1-1-1`.`status` != 'obsolete')",
+				'parent_att' => 'service_id',
+				'result' => "SELECT `L-1-1` FROM Service AS `L-1-1` JOIN lnkCustomerContractToService AS `l1` ON `l1`.service_id = `L-1-1`.id JOIN CustomerContract AS `cc` ON `l1`.customercontract_id = `cc`.id JOIN ServiceSubcategory AS `L-1-1-1` ON `L-1-1-1`.service_id = `L-1-1`.id WHERE (((`cc`.`org_id` = 2) AND (`L-1-1`.`status` != 'obsolete')) AND (`L-1-1-1`.`status` != 'obsolete')) UNION SELECT `L-1-1` FROM Service AS `L-1-1` JOIN lnkCustomerContractToService AS `l11` ON `l11`.service_id = `L-1-1`.id JOIN CustomerContract AS `cc1` ON `l11`.customercontract_id = `cc1`.id JOIN Organization AS `child` ON `cc1`.org_id = `child`.id JOIN Organization AS `root` ON `child`.parent_id BELOW `root`.id JOIN ServiceSubcategory AS `L-1-1-1` ON `L-1-1-1`.service_id = `L-1-1`.id WHERE (((`root`.`id` = 2) AND (`L-1-1`.`status` != 'obsolete')) AND (`L-1-1-1`.`status` != 'obsolete'))",
+			],
+			'Bug 2970' => [
+				'left' => "SELECT `L-1-1` FROM Service AS `L-1-1` JOIN lnkCustomerContractToService AS `l1` ON `l1`.service_id = `L-1-1`.id JOIN CustomerContract AS `cc` ON `l1`.customercontract_id = `cc`.id WHERE ((`cc`.`org_id` = 2) AND (`L-1-1`.`status` != 'obsolete')) UNION SELECT `L-1-1` FROM Service AS `L-1-1` WHERE (`L-1-1`.`id` = 8)",
+				'right' => "SELECT `L-1-1-1` FROM ServiceSubcategory AS `L-1-1-1` JOIN Service AS `s` ON `L-1-1-1`.service_id = `s`.id JOIN lnkCustomerContractToService AS `l1` ON `l1`.service_id = `s`.id JOIN CustomerContract AS `cc` ON `l1`.customercontract_id = `cc`.id WHERE ((`L-1-1-1`.`status` != 'obsolete') AND ((`cc`.`org_id` = 2) AND (`L-1-1-1`.`status` != 'obsolete'))) UNION SELECT `L-1-1-1` FROM ServiceSubcategory AS `L-1-1-1` JOIN Service AS `s1` ON `L-1-1-1`.service_id = `s1`.id WHERE ((`L-1-1-1`.`status` != 'obsolete') AND (`s1`.`id` = 8))",
+				'parent_att' => 'service_id',
+				'result' => "SELECT `L-1-1` FROM Service AS `L-1-1` JOIN lnkCustomerContractToService AS `l1` ON `l1`.service_id = `L-1-1`.id JOIN CustomerContract AS `cc` ON `l1`.customercontract_id = `cc`.id JOIN ServiceSubcategory AS `L-1-1-1` ON `L-1-1-1`.service_id = `L-1-1`.id WHERE (((`cc`.`org_id` = 2) AND (`L-1-1`.`status` != 'obsolete')) AND ((`L-1-1-1`.`status` != 'obsolete') AND ((`cc`.`org_id` = 2) AND (`L-1-1-1`.`status` != 'obsolete')))) UNION SELECT `L-1-1` FROM Service AS `L-1-1` JOIN ServiceSubcategory AS `L-1-1-1` ON `L-1-1-1`.service_id = `L-1-1`.id JOIN lnkCustomerContractToService AS `l11` ON `l11`.service_id = `L-1-1`.id JOIN CustomerContract AS `cc1` ON `l11`.customercontract_id = `cc1`.id WHERE ((`L-1-1`.`id` = 8) AND ((`L-1-1-1`.`status` != 'obsolete') AND ((`cc1`.`org_id` = 2) AND (`L-1-1-1`.`status` != 'obsolete')))) UNION SELECT `L-1-1` FROM Service AS `L-1-1` JOIN lnkCustomerContractToService AS `l1` ON `l1`.service_id = `L-1-1`.id JOIN CustomerContract AS `cc` ON `l1`.customercontract_id = `cc`.id JOIN ServiceSubcategory AS `L-1-1-1` ON `L-1-1-1`.service_id = `L-1-1`.id WHERE (((`cc`.`org_id` = 2) AND (`L-1-1`.`status` != 'obsolete')) AND ((`L-1-1-1`.`status` != 'obsolete') AND (`L-1-1`.`id` = 8))) UNION SELECT `L-1-1` FROM Service AS `L-1-1` JOIN ServiceSubcategory AS `L-1-1-1` ON `L-1-1-1`.service_id = `L-1-1`.id WHERE ((`L-1-1`.`id` = 8) AND ((`L-1-1-1`.`status` != 'obsolete') AND (`L-1-1`.`id` = 8)))",
+			],
+//			'test' => [
+//				'left' => "",
+//				'right' => "",
+//				'parent_att' => '',
+//				'result' => "",
+//			],
+		];
+	}
+}