diff --git a/src-db/database/model/triggers/M_CH_VALUE_TRG.xml b/src-db/database/model/triggers/M_CH_VALUE_TRG.xml
--- a/src-db/database/model/triggers/M_CH_VALUE_TRG.xml
+++ b/src-db/database/model/triggers/M_CH_VALUE_TRG.xml
@@ -73,7 +73,9 @@
       pch.m_product_ch_id, :new.m_ch_value_id, :new.skcode
       FROM m_product_ch pch
       WHERE pch.m_characteristic_id = :new.m_characteristic_id
-        AND pch.m_ch_subset_id IS NULL;
+        AND pch.m_ch_subset_id IS NULL
+        AND exists (select 1 from  m_product where m_product_id=pch.m_product_id AND isgeneric='Y')
+        AND pch.isvariant='Y';
   END IF;
 
   IF DELETING THEN