diff --git a/harvesters/src/main/java/org/fao/geonet/kernel/harvest/harvester/csw/Aligner.java b/harvesters/src/main/java/org/fao/geonet/kernel/harvest/harvester/csw/Aligner.java
index 88942e4ec86..5097d9a600c 100644
--- a/harvesters/src/main/java/org/fao/geonet/kernel/harvest/harvester/csw/Aligner.java
+++ b/harvesters/src/main/java/org/fao/geonet/kernel/harvest/harvester/csw/Aligner.java
@@ -1,5 +1,5 @@
 //=============================================================================
-//===	Copyright (C) 2001-2007 Food and Agriculture Organization of the
+//===	Copyright (C) 2001-2024 Food and Agriculture Organization of the
 //===	United Nations (FAO-UN), United Nations World Food Programme (WFP)
 //===	and United Nations Environment Programme (UNEP)
 //===
@@ -232,7 +232,7 @@ private void insertOrUpdate(Collection<RecordInfo> records, Collection<HarvestEr
                 }
 
                 result.totalMetadata++;
-            } catch (Throwable t) {
+            } catch (Exception t) {
                 errors.add(new HarvestError(this.context, t));
                 log.error("Unable to process record from csw (" + this.params.getName() + ")");
                 log.error("   Record failed: " + ri.uuid + ". Error is: " + t.getMessage());
@@ -285,7 +285,6 @@ private void addMetadata(RecordInfo ri, String uuidToAssign) throws Exception {
         Element md = retrieveMetadata(ri.uuid);
 
         if (md == null) {
-            result.unretrievable++;
             return;
         }
 
@@ -404,7 +403,7 @@ public static void applyBatchEdits(
                     if (StringUtils.isNotEmpty(batchEditParameter.getCondition())) {
                         applyEdit = false;
                         final Object node = Xml.selectSingle(md, batchEditParameter.getCondition(), metadataSchema.getNamespaces());
-                        if (node != null && node instanceof Boolean && (Boolean)node == true) {
+                        if (node instanceof Boolean && Boolean.TRUE.equals(node)) {
                             applyEdit = true;
                         }
                     }
@@ -424,7 +423,7 @@ public static void applyBatchEdits(
             }
         }
     }
-    private void updateMetadata(RecordInfo ri, String id, Boolean force) throws Exception {
+    private void updateMetadata(RecordInfo ri, String id, boolean force) throws Exception {
         String date = localUuids.getChangeDate(ri.uuid);
 
         if (date == null && !force) {
@@ -443,11 +442,10 @@ private void updateMetadata(RecordInfo ri, String id, Boolean force) throws Exce
         }
     }
     @Transactional(value = TxType.REQUIRES_NEW)
-    boolean updatingLocalMetadata(RecordInfo ri, String id, Boolean force) throws Exception {
+    boolean updatingLocalMetadata(RecordInfo ri, String id, boolean force) throws Exception {
         Element md = retrieveMetadata(ri.uuid);
 
         if (md == null) {
-            result.unchangedMetadata++;
             return false;
         }
 
@@ -500,8 +498,11 @@ boolean updatingLocalMetadata(RecordInfo ri, String id, Boolean force) throws Ex
     }
 
     /**
-     * Does CSW GetRecordById request. If validation is requested and the metadata does not
-     * validate, null is returned.
+     * Does CSW GetRecordById request. Returns null on error conditions:
+     *  - If validation is requested and the metadata does not validate.
+     *  - No metadata is retrieved.
+     *  - If metadata resource is duplicated.
+     *  - An exception occurs retrieving the metadata.
      *
      * @param uuid uuid of metadata to request
      * @return metadata the metadata
@@ -524,6 +525,7 @@ private Element retrieveMetadata(String uuid) {
             //--- maybe the metadata has been removed
 
             if (list.isEmpty()) {
+                result.unretrievable++;
                 return null;
             }
 
@@ -544,11 +546,10 @@ private Element retrieveMetadata(String uuid) {
                 return null;
             }
 
-            if (params.rejectDuplicateResource) {
-                if (foundDuplicateForResource(uuid, response)) {
+            if (params.rejectDuplicateResource && (foundDuplicateForResource(uuid, response))) {
                     result.unchangedMetadata++;
                     return null;
-                }
+
             }
 
             return response;
@@ -612,7 +613,7 @@ private boolean foundDuplicateForResource(String uuid, Element response) {
                         }
                     }
                 }
-            } catch (Throwable e) {
+            } catch (Exception e) {
                 log.warning("      - Error when searching for resource duplicate " + uuid + ". Error is: " + e.getMessage());
             }
         }