diff --git a/dhp-workflows/dhp-dedup-openaire/src/main/java/eu/dnetlib/dhp/oa/dedup/RelationAggregator.java b/dhp-workflows/dhp-dedup-openaire/src/main/java/eu/dnetlib/dhp/oa/dedup/RelationAggregator.java
index 7935fe1ca..6fb7b844b 100644
--- a/dhp-workflows/dhp-dedup-openaire/src/main/java/eu/dnetlib/dhp/oa/dedup/RelationAggregator.java
+++ b/dhp-workflows/dhp-dedup-openaire/src/main/java/eu/dnetlib/dhp/oa/dedup/RelationAggregator.java
@@ -20,13 +20,12 @@ public class RelationAggregator extends Aggregator<Relation, Relation, Relation>
 
 	@Override
 	public Relation reduce(Relation b, Relation a) {
-		return Objects.equals(a, ZERO) ? b : a;
+		return mergeRel(b, a);
 	}
 
 	@Override
 	public Relation merge(Relation b, Relation a) {
-		b.mergeFrom(a);
-		return b;
+		return mergeRel(b, a);
 	}
 
 	@Override
@@ -34,6 +33,18 @@ public class RelationAggregator extends Aggregator<Relation, Relation, Relation>
 		return r;
 	}
 
+	private Relation mergeRel(Relation b, Relation a) {
+		if (Objects.equals(b, ZERO)) {
+			return a;
+		}
+		if (Objects.equals(a, ZERO)) {
+			return b;
+		}
+
+		b.mergeFrom(a);
+		return b;
+	}
+
 	@Override
 	public Encoder<Relation> bufferEncoder() {
 		return Encoders.kryo(Relation.class);
diff --git a/dhp-workflows/dhp-dedup-openaire/src/main/java/eu/dnetlib/dhp/oa/dedup/SparkPropagateRelation.java b/dhp-workflows/dhp-dedup-openaire/src/main/java/eu/dnetlib/dhp/oa/dedup/SparkPropagateRelation.java
index baba3bc87..1073adbea 100644
--- a/dhp-workflows/dhp-dedup-openaire/src/main/java/eu/dnetlib/dhp/oa/dedup/SparkPropagateRelation.java
+++ b/dhp-workflows/dhp-dedup-openaire/src/main/java/eu/dnetlib/dhp/oa/dedup/SparkPropagateRelation.java
@@ -3,6 +3,7 @@ package eu.dnetlib.dhp.oa.dedup;
 
 import static org.apache.spark.sql.functions.col;
 
+import com.google.common.base.Joiner;
 import org.apache.commons.io.IOUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.spark.SparkConf;
@@ -108,7 +109,7 @@ public class SparkPropagateRelation extends AbstractSparkAction {
 	private Dataset<Relation> distinctRelations(Dataset<Relation> rels) {
 		return rels
 			.filter(getRelationFilterFunction())
-			.groupByKey((MapFunction<Relation, String>) r -> ModelSupport.idFn().apply(r), Encoders.STRING())
+			.groupByKey((MapFunction<Relation, String>) r -> String.join(r.getSource(), r.getTarget(), r.getRelType(), r.getSubRelType(), r.getRelClass()), Encoders.STRING())
 			.agg(new RelationAggregator().toColumn())
 			.map((MapFunction<Tuple2<String, Relation>, Relation>) t -> t._2(), Encoders.bean(Relation.class));
 	}