diff --git a/src/main/java/org/opensearch/neuralsearch/search/HybridTopScoreDocCollector.java b/src/main/java/org/opensearch/neuralsearch/search/HybridTopScoreDocCollector.java
index 79b134b38..4418841f4 100644
--- a/src/main/java/org/opensearch/neuralsearch/search/HybridTopScoreDocCollector.java
+++ b/src/main/java/org/opensearch/neuralsearch/search/HybridTopScoreDocCollector.java
@@ -56,9 +56,15 @@ public LeafCollector getLeafCollector(LeafReaderContext context) {
             @Override
             public void setScorer(Scorable scorer) throws IOException {
                 if (scorer instanceof HybridQueryScorer) {
+                    log.debug("passed scorer is of type HybridQueryScorer, saving it for collecting documents and scores");
                     compoundQueryScorer = (HybridQueryScorer) scorer;
                 } else {
                     compoundQueryScorer = getHybridQueryScorer(scorer);
+                    if (Objects.isNull(compoundQueryScorer)) {
+                        log.error(
+                            String.format(Locale.ROOT, "cannot find scorer of type HybridQueryScorer in a hierarchy of scorer %s", scorer)
+                        );
+                    }
                 }
             }
 
@@ -71,7 +77,14 @@ private HybridQueryScorer getHybridQueryScorer(final Scorable scorer) throws IOE
                 }
                 for (Scorable.ChildScorable childScorable : scorer.getChildren()) {
                     HybridQueryScorer hybridQueryScorer = getHybridQueryScorer(childScorable.child);
-                    if (hybridQueryScorer != null) {
+                    if (Objects.nonNull(hybridQueryScorer)) {
+                        log.debug(
+                            String.format(
+                                Locale.ROOT,
+                                "found hybrid query scorer, it's child of scorer %s",
+                                childScorable.child.getClass().getSimpleName()
+                            )
+                        );
                         return hybridQueryScorer;
                     }
                 }
diff --git a/src/main/java/org/opensearch/neuralsearch/search/query/HybridAggregationProcessor.java b/src/main/java/org/opensearch/neuralsearch/search/query/HybridAggregationProcessor.java
index 8b584feea..42c27821f 100644
--- a/src/main/java/org/opensearch/neuralsearch/search/query/HybridAggregationProcessor.java
+++ b/src/main/java/org/opensearch/neuralsearch/search/query/HybridAggregationProcessor.java
@@ -47,8 +47,14 @@ public void preProcess(SearchContext context) {
     public void postProcess(SearchContext context) {
         if (isHybridQuery(context.query(), context)) {
             // for case when concurrent search is not enabled (default as of 2.12 release) reduce for collector
-            // managers is not called, and we have to call it manually. This is required as we format final
+            // managers is not called
+            // (https://github.com/opensearch-project/OpenSearch/blob/2.12/server/src/main/java/org/opensearch/search/query/QueryPhase.java#L333-L373)
+            // and we have to call it manually. This is required as we format final
             // result of hybrid query in {@link HybridTopScoreCollector#reduce}
+            // when concurrent search is enabled then reduce method is called as part of the search {@see
+            // ConcurrentQueryPhaseSearcher#searchWithCollectorManager}
+            // corresponding call in Lucene
+            // https://github.com/apache/lucene/blob/branch_9_10/lucene/core/src/java/org/apache/lucene/search/IndexSearcher.java#L700
             if (!context.shouldUseConcurrentSearch()) {
                 reduceCollectorResults(context);
             }