diff --git a/core/attributedef.class.inc.php b/core/attributedef.class.inc.php
index 642f990ed..2259cbc16 100644
--- a/core/attributedef.class.inc.php
+++ b/core/attributedef.class.inc.php
@@ -6830,15 +6830,10 @@ class AttributeTagSet extends AttributeDBFieldVoid
 				$aGoodTags[] = $sTagCode;
 				if (count($aGoodTags) === $this->GetTagMaxNb())
 				{
-					// extra tags are ignored
+					// extra and bad tags are ignored
 					continue;
 				}
 			}
-			else
-			{
-				// Ignore bad tags from database
-				IssueLog::Warning("Unknown tag $sTagCode for $sClass::$sAttCode found in database, ignored.");
-			}
 		}
 		$oTagSet->SetValue($aGoodTags);
 
@@ -7082,36 +7077,12 @@ class AttributeTagSet extends AttributeDBFieldVoid
 
 		$aAllowedTags = TagSetFieldData::GetAllowedValues(MetaModel::GetAttributeOrigin($this->GetHostClass(), $this->GetCode()), $this->GetCode());
 
-		if (!empty($aDelta['added']))
-		{
-			$aAdded = array();
-			foreach($aDelta['added'] as $idx => $sTagCode)
-			{
-				$sTagLabel = $sTagCode;
-				foreach($aAllowedTags as $oTag)
-				{
-					if ($sTagCode === $oTag->Get('tag_code'))
-					{
-						$sTagLabel = $oTag->Get('tag_label');
-					}
-				}
-				$aAdded[] = $sTagLabel;
-			}
-
-			$sAdded = $this->GenerateViewHtmlForValues($aAdded);
-			$sResult .= Dict::Format('Change:LinkSet:Added', $sAdded);
-		}
-
 		if (!empty($aDelta['removed']))
 		{
-			if (!empty($sAdded))
-			{
-				$sResult .= ', ';
-			}
-
 			$aRemoved = array();
 			foreach($aDelta['removed'] as $idx => $sTagCode)
 			{
+				if (empty($sTagCode)) {continue;}
 				$sTagLabel = $sTagCode;
 				foreach($aAllowedTags as $oTag)
 				{
@@ -7124,7 +7095,39 @@ class AttributeTagSet extends AttributeDBFieldVoid
 			}
 
 			$sRemoved = $this->GenerateViewHtmlForValues($aRemoved);
-			$sResult .= Dict::Format('Change:LinkSet:Removed', $sRemoved);
+			if (!empty($sRemoved))
+			{
+				$sResult .= Dict::Format('Change:LinkSet:Removed', $sRemoved);
+			}
+		}
+
+		if (!empty($aDelta['added']))
+		{
+			if (!empty($sRemoved))
+			{
+				$sResult .= ', ';
+			}
+
+			$aAdded = array();
+			foreach($aDelta['added'] as $idx => $sTagCode)
+			{
+				if (empty($sTagCode)) {continue;}
+				$sTagLabel = $sTagCode;
+				foreach($aAllowedTags as $oTag)
+				{
+					if ($sTagCode === $oTag->Get('tag_code'))
+					{
+						$sTagLabel = $oTag->Get('tag_label');
+					}
+				}
+				$aAdded[] = $sTagLabel;
+			}
+
+			$sAdded = $this->GenerateViewHtmlForValues($aAdded);
+			if (!empty($sAdded))
+			{
+				$sResult .= Dict::Format('Change:LinkSet:Added', $sAdded);
+			}
 		}
 
 		return $sResult;
@@ -7142,6 +7145,7 @@ class AttributeTagSet extends AttributeDBFieldVoid
 	 */
 	private function GenerateViewHtmlForValues($aValues, $sCssClass = 'attribute-tagset')
 	{
+		if (empty($aValues)) {return '';}
 		$sHtml = '<span class="'.$sCssClass.'">';
 		foreach($aValues as $oTag)
 		{
diff --git a/core/metamodel.class.php b/core/metamodel.class.php
index 004530f7a..c1ba6c964 100644
--- a/core/metamodel.class.php
+++ b/core/metamodel.class.php
@@ -7103,12 +7103,6 @@ abstract class MetaModel
 		return $sRet;
 	}
 
-	public static function GetTagDataClass($sClass, $sAttCode)
-    {
-        $sTagSuffix = $sClass.'_'.$sAttCode;
-        return 'TagSetFieldDataFor_'.$sTagSuffix;
-    }
-
 }
 
 
diff --git a/core/ormtagset.class.inc.php b/core/ormtagset.class.inc.php
index 4849ea1bc..729063533 100644
--- a/core/ormtagset.class.inc.php
+++ b/core/ormtagset.class.inc.php
@@ -595,7 +595,7 @@ final class ormTagSet
 
 	public function GetTagDataClass()
 	{
-		return MetaModel::GetTagDataClass($this->sClass, $this->sAttCode);
+		return TagSetFieldData::GetTagDataClassName($this->sClass, $this->sAttCode);
 	}
 
 }
\ No newline at end of file
diff --git a/core/tagsetfield.class.inc.php b/core/tagsetfield.class.inc.php
index 0087beef6..3980efd0f 100644
--- a/core/tagsetfield.class.inc.php
+++ b/core/tagsetfield.class.inc.php
@@ -101,6 +101,13 @@ abstract class TagSetFieldData extends cmdbAbstractObject
 		$this->_Set('tag_attcode', $aRes['tag_attcode']);
 	}
 
+	public static function GetTagDataClassName($sClass, $sAttCode)
+	{
+		$sTagSuffix = $sClass.'__'.$sAttCode;
+
+		return 'TagSetFieldDataFor_'.$sTagSuffix;
+	}
+
 	/**
 	 * Extract Tag class and attcode from the TagFieldData class name
 	 *
@@ -113,7 +120,7 @@ abstract class TagSetFieldData extends cmdbAbstractObject
 	{
 		$aRes = array();
 		// Extract class and attcode from class name using pattern  TagSetFieldDataFor_<class>_<attcode>>;
-		if (preg_match('@^TagSetFieldDataFor_(?<class>\w+)_(?<attcode>\w+)$@', $sClassName, $aMatches))
+		if (preg_match('@^TagSetFieldDataFor_(?<class>\w+)__(?<attcode>\w+)$@', $sClassName, $aMatches))
 		{
 			$aRes['tag_class'] = $aMatches['class'];
 			$aRes['tag_attcode'] = $aMatches['attcode'];
@@ -144,7 +151,7 @@ abstract class TagSetFieldData extends cmdbAbstractObject
 			$this->m_aDeleteIssues[] = Dict::S('Core:TagSetFieldData:ErrorDeleteUsedTag');
 		}
 		// Clear cache
-		$sTagDataClass = MetaModel::GetTagDataClass($sClass, $sAttCode);
+		$sTagDataClass = self::GetTagDataClassName($sClass, $sAttCode);
 		unset(self::$m_aAllowedValues[$sTagDataClass]);
 	}
 
@@ -199,7 +206,7 @@ abstract class TagSetFieldData extends cmdbAbstractObject
 			$this->m_aCheckIssues[] = Dict::S('Core:TagSetFieldData:ErrorDuplicateTagCodeOrLabel');
 		}
 		// Clear cache
-		$sTagDataClass = MetaModel::GetTagDataClass($sClass, $sAttCode);
+		$sTagDataClass = self::GetTagDataClassName($sClass, $sAttCode);
 		unset(self::$m_aAllowedValues[$sTagDataClass]);
 
 		parent::DoCheckToWrite();
@@ -275,7 +282,7 @@ abstract class TagSetFieldData extends cmdbAbstractObject
 	{
 		try
 		{
-			$aTagFieldInfo = TagSetFieldData::ExtractTagFieldName($sClass);
+			$aTagFieldInfo = self::ExtractTagFieldName($sClass);
 		} catch (CoreException $e)
 		{
 			return $sClass;
@@ -305,7 +312,7 @@ abstract class TagSetFieldData extends cmdbAbstractObject
 	public static function GetAllowedValues($sClass, $sAttCode)
 	{
 		$sClass = MetaModel::GetAttributeOrigin($sClass, $sAttCode);
-		$sTagDataClass = MetaModel::GetTagDataClass($sClass, $sAttCode);
+		$sTagDataClass = self::GetTagDataClassName($sClass, $sAttCode);
 		if (!isset(self::$m_aAllowedValues[$sTagDataClass]))
 		{
 			$oSearch = new DBObjectSearch($sTagDataClass);
diff --git a/setup/compiler.class.inc.php b/setup/compiler.class.inc.php
index c69ec826e..d3002c639 100644
--- a/setup/compiler.class.inc.php
+++ b/setup/compiler.class.inc.php
@@ -1855,8 +1855,7 @@ EOF;
 			);
 			foreach ($aTagFieldsInfo as $sTagFieldName)
 			{
-				$sTagSuffix = $sClassName.'_'.$sTagFieldName;
-				$sTagClassName = 'TagSetFieldDataFor_'.$sTagSuffix;
+				$sTagClassName = static::GetTagDataClassName($sClassName, $sTagFieldName);
 				$sTagClassParams = var_export($aTagClassParams, true);
 				$sPHP .= $this->GeneratePhpCodeForClass($sTagClassName, $sTagClassParentClass, $sTagClassParams);
 			}
@@ -1865,6 +1864,12 @@ EOF;
 		return $sPHP;
 	}
 
+	private static function GetTagDataClassName($sClass, $sAttCode)
+	{
+		$sTagSuffix = $sClass.'__'.$sAttCode;
+
+		return 'TagSetFieldDataFor_'.$sTagSuffix;
+	}
 
 	/**
 	 * @param $oMenu
diff --git a/test/ItopDataTestCase.php b/test/ItopDataTestCase.php
index e000323f2..fc5f8cbaa 100644
--- a/test/ItopDataTestCase.php
+++ b/test/ItopDataTestCase.php
@@ -38,6 +38,7 @@ use lnkContactToFunctionalCI;
 use MetaModel;
 use Person;
 use Server;
+use TagSetFieldData;
 use Ticket;
 use URP_UserProfile;
 use VirtualHost;
@@ -223,7 +224,7 @@ class ItopDataTestCase extends ItopTestCase
 	 */
 	protected function CreateTagData($sClass, $sAttCode, $sTagCode, $sTagLabel, $sTagDescription = '')
 	{
-		$sTagClass = MetaModel::GetTagDataClass($sClass, $sAttCode);
+		$sTagClass = TagSetFieldData::GetTagDataClassName($sClass, $sAttCode);
 		$oTagData = $this->createObject($sTagClass, array(
 			'tag_code' => $sTagCode,
 			'tag_label' => $sTagLabel,
@@ -248,7 +249,7 @@ class ItopDataTestCase extends ItopTestCase
 	 */
 	protected function RemoveTagData($sClass, $sAttCode, $sTagCode)
 	{
-		$sTagClass = MetaModel::GetTagDataClass($sClass, $sAttCode);
+		$sTagClass = TagSetFieldData::GetTagDataClassName($sClass, $sAttCode);
 		$this->RemoveObjects($sTagClass, "SELECT $sTagClass WHERE tag_code = '$sTagCode'");
 	}
 
diff --git a/test/core/TagSetFieldDataTest.php b/test/core/TagSetFieldDataTest.php
index 4ba862d46..83e989d36 100644
--- a/test/core/TagSetFieldDataTest.php
+++ b/test/core/TagSetFieldDataTest.php
@@ -129,7 +129,7 @@ class TagSetFieldDataTest extends ItopDataTestCase
 	 */
 	public function testComputeValues()
 	{
-		$sTagClass = \MetaModel::GetTagDataClass(TAG_CLASS, TAG_ATTCODE);
+		$sTagClass = TagSetFieldData::GetTagDataClassName(TAG_CLASS, TAG_ATTCODE);
 		$oTagData = $this->createObject($sTagClass, array(
 			'tag_code' => 'tag1',
 			'tag_label' => 'First',