diff --git a/docs/changelog/112761.yaml b/docs/changelog/112761.yaml
new file mode 100644
index 0000000000000..fe63f38f365a4
--- /dev/null
+++ b/docs/changelog/112761.yaml
@@ -0,0 +1,6 @@
+pr: 112761
+summary: Fix collapse interaction with stored fields
+area: Search
+type: bug
+issues:
+ - 112646
diff --git a/server/src/internalClusterTest/java/org/elasticsearch/search/CollapseSearchResultsIT.java b/server/src/internalClusterTest/java/org/elasticsearch/search/CollapseSearchResultsIT.java
index 48dda7fd30068..89474a0181597 100644
--- a/server/src/internalClusterTest/java/org/elasticsearch/search/CollapseSearchResultsIT.java
+++ b/server/src/internalClusterTest/java/org/elasticsearch/search/CollapseSearchResultsIT.java
@@ -14,6 +14,7 @@
 import org.elasticsearch.index.query.MatchAllQueryBuilder;
 import org.elasticsearch.search.collapse.CollapseBuilder;
 import org.elasticsearch.test.ESIntegTestCase;
+import org.elasticsearch.xcontent.XContentType;
 
 import java.util.Map;
 import java.util.Set;
@@ -85,4 +86,33 @@ public void testCollapseWithFields() {
             }
         );
     }
+
+    public void testCollapseWithStoredFields() {
+        final String indexName = "test_collapse";
+        createIndex(indexName);
+        final String collapseField = "collapse_field";
+        assertAcked(indicesAdmin().preparePutMapping(indexName).setSource("""
+                     {
+                       "dynamic": "strict",
+                       "properties": {
+                         "collapse_field":  { "type": "keyword", "store": true },
+                         "ts":  { "type": "date", "store": true }
+                       }
+                     }
+            """, XContentType.JSON));
+        index(indexName, "id_1_0", Map.of(collapseField, "value1", "ts", 0));
+        index(indexName, "id_1_1", Map.of(collapseField, "value1", "ts", 1));
+        index(indexName, "id_2_0", Map.of(collapseField, "value2", "ts", 2));
+        refresh(indexName);
+
+        assertNoFailuresAndResponse(
+            prepareSearch(indexName).setQuery(new MatchAllQueryBuilder())
+                .setFetchSource(false)
+                .storedFields("*")
+                .setCollapse(new CollapseBuilder(collapseField)),
+            searchResponse -> {
+                assertEquals(collapseField, searchResponse.getHits().getCollapseField());
+            }
+        );
+    }
 }
diff --git a/server/src/main/java/org/elasticsearch/search/fetch/subphase/StoredFieldsPhase.java b/server/src/main/java/org/elasticsearch/search/fetch/subphase/StoredFieldsPhase.java
index b3211f0b1e31c..17b57645d7d5f 100644
--- a/server/src/main/java/org/elasticsearch/search/fetch/subphase/StoredFieldsPhase.java
+++ b/server/src/main/java/org/elasticsearch/search/fetch/subphase/StoredFieldsPhase.java
@@ -27,6 +27,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 /**
  * Process stored fields loaded from a HitContext into DocumentFields
@@ -42,7 +43,8 @@ List<Object> process(Map<String, List<Object>> loadedFields) {
             if (inputs == null) {
                 return List.of();
             }
-            return inputs.stream().map(ft::valueForDisplay).toList();
+            // This is eventually provided to DocumentField, which needs this collection to be mutable
+            return inputs.stream().map(ft::valueForDisplay).collect(Collectors.toList());
         }
 
         boolean hasValue(Map<String, List<Object>> loadedFields) {