diff --git a/x-pack/plugin/logsdb/src/javaRestTest/java/org/elasticsearch/xpack/logsdb/patterntext/PatternTextLicenseDowngradeIT.java b/x-pack/plugin/logsdb/src/javaRestTest/java/org/elasticsearch/xpack/logsdb/patterntext/PatternTextLicenseDowngradeIT.java
index e6f8ec12075d7..04f4f4847d4a0 100644
--- a/x-pack/plugin/logsdb/src/javaRestTest/java/org/elasticsearch/xpack/logsdb/patterntext/PatternTextLicenseDowngradeIT.java
+++ b/x-pack/plugin/logsdb/src/javaRestTest/java/org/elasticsearch/xpack/logsdb/patterntext/PatternTextLicenseDowngradeIT.java
@@ -7,14 +7,23 @@
 
 package org.elasticsearch.xpack.logsdb.patterntext;
 
+import org.elasticsearch.client.Request;
+import org.elasticsearch.client.Response;
+import org.elasticsearch.test.rest.ObjectPath;
 import org.elasticsearch.xpack.logsdb.DataStreamLicenseChangeTestCase;
 import org.junit.Before;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
+import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasEntry;
 import static org.hamcrest.Matchers.hasKey;
+import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.not;
 
 public class PatternTextLicenseDowngradeIT extends DataStreamLicenseChangeTestCase {
@@ -54,9 +63,25 @@ public void testLicenseDowngrade() throws IOException {
             assertThat(patternFieldMapping, not(hasKey("disable_templating")));
         }
 
+        // Index docs while on trial license (templating enabled)
+        List<String> preDowngradeDocs = List.of("foo 123 bar", "baz 456 qux", "hello 789 world");
+        indexDocs(dataStreamName, preDowngradeDocs);
+
+        // Verify search returns pre-downgrade docs
+        assertSearchReturnsValues(preDowngradeDocs);
+
         startBasic();
-        rolloverDataStream(client(), dataStreamName);
 
+        // Index docs after downgrade into the same backing index (still has disable_templating=false)
+        List<String> postDowngradeDocs = List.of("post downgrade 111", "another post 222");
+        indexDocs(dataStreamName, postDowngradeDocs);
+
+        // Verify search returns all docs from before and after downgrade
+        List<String> allDocsBeforeRollover = new ArrayList<>(preDowngradeDocs);
+        allDocsBeforeRollover.addAll(postDowngradeDocs);
+        assertSearchReturnsValues(allDocsBeforeRollover);
+
+        // Original backing index settings remain unchanged after downgrade
         {
             assertEquals("false", getSetting(client(), backingIndex0, "index.mapping.pattern_text.disable_templating"));
             Map<String, Object> mapping = getMapping(client(), backingIndex0);
@@ -66,6 +91,8 @@ public void testLicenseDowngrade() throws IOException {
             assertThat(patternFieldMapping, not(hasKey("disable_templating")));
         }
 
+        rolloverDataStream(client(), dataStreamName);
+
         String backingIndex1 = getDataStreamBackingIndex(client(), dataStreamName, 1);
         {
             assertEquals("true", getSetting(client(), backingIndex1, "index.mapping.pattern_text.disable_templating"));
@@ -76,5 +103,76 @@ public void testLicenseDowngrade() throws IOException {
             assertThat(patternFieldMapping, hasEntry("disable_templating", true));
         }
 
+        // Index docs into the new (downgraded) backing index
+        List<String> postRolloverDocs = List.of("rolled over 333", "new index 444", "downgraded 555");
+        indexDocs(dataStreamName, postRolloverDocs);
+
+        // Verify search across all backing indices returns every doc
+        List<String> allDocs = new ArrayList<>(allDocsBeforeRollover);
+        allDocs.addAll(postRolloverDocs);
+        assertSearchReturnsValues(allDocs);
+
+        // Fetch pattern_field via the "fields" parameter, which exercises the valueFetcher() code path.
+        // With disabled templating, valueFetcher must load values from binary doc values or stored fields
+        // rather than from pattern_text template+args doc values.
+        assertFieldsFetchReturnsValues(allDocs);
+    }
+
+    private static void indexDocs(String dataStreamName, List<String> values) throws IOException {
+        StringBuilder sb = new StringBuilder();
+        for (String value : values) {
+            sb.append("{\"create\": {}}\n");
+            sb.append("{\"pattern_field\": \"").append(value).append("\"}\n");
+        }
+        assertOK(bulkIndex(client(), dataStreamName, sb::toString));
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void assertSearchReturnsValues(List<String> expectedValues) throws IOException {
+        Request searchRequest = new Request("GET", "/" + "logs-test-pattern-text" + "/_search");
+        searchRequest.setJsonEntity("""
+            {
+                "query": {"match_all": {}},
+                "size": 100
+            }
+            """);
+        Response response = client().performRequest(searchRequest);
+        assertThat(response.getStatusLine().getStatusCode(), is(200));
+        ObjectPath objectPath = ObjectPath.createFromResponse(response);
+
+        assertThat(objectPath.evaluate("hits.total.value"), equalTo(expectedValues.size()));
+        List<Map<String, Object>> hits = objectPath.evaluate("hits.hits");
+        Set<String> actual = new HashSet<>();
+        for (Map<String, Object> hit : hits) {
+            Map<String, Object> source = (Map<String, Object>) hit.get("_source");
+            actual.add((String) source.get("pattern_field"));
+        }
+        assertEquals(new HashSet<>(expectedValues), actual);
+    }
+
+    @SuppressWarnings("unchecked")
+    private static void assertFieldsFetchReturnsValues(List<String> expectedValues) throws IOException {
+        Request searchRequest = new Request("GET", "/" + "logs-test-pattern-text" + "/_search");
+        searchRequest.setJsonEntity("""
+            {
+                "query": {"match_all": {}},
+                "fields": ["pattern_field"],
+                "size": 100
+            }
+            """);
+        Response response = client().performRequest(searchRequest);
+        assertThat(response.getStatusLine().getStatusCode(), is(200));
+        ObjectPath objectPath = ObjectPath.createFromResponse(response);
+
+        assertThat(objectPath.evaluate("hits.total.value"), equalTo(expectedValues.size()));
+        List<Map<String, Object>> hits = objectPath.evaluate("hits.hits");
+        Set<String> actual = new HashSet<>();
+        for (Map<String, Object> hit : hits) {
+            Map<String, Object> fields = (Map<String, Object>) hit.get("fields");
+            List<String> values = (List<String>) fields.get("pattern_field");
+            assertThat(values.size(), equalTo(1));
+            actual.add(values.get(0));
+        }
+        assertEquals(new HashSet<>(expectedValues), actual);
     }
 }