diff --git a/server/src/main/java/org/opensearch/index/remote/RemoteStoreUtils.java b/server/src/main/java/org/opensearch/index/remote/RemoteStoreUtils.java
index efbe4534bf0ef..32a1ca0e5d5ab 100644
--- a/server/src/main/java/org/opensearch/index/remote/RemoteStoreUtils.java
+++ b/server/src/main/java/org/opensearch/index/remote/RemoteStoreUtils.java
@@ -476,7 +476,8 @@ private static Set<String> getPinnedTimestampLockedFiles(
         Set<Long> newPinnedTimestamps = new TreeSet<>(Collections.reverseOrder());
         for (Long pinnedTimestamp : pinnedTimestampSet) {
             String cachedFile = metadataFilePinnedTimestampMap.get(pinnedTimestamp);
-            if (cachedFile != null && metadataFiles.contains(cachedFile)) {
+            if (cachedFile != null) {
+                assert metadataFiles.contains(cachedFile) : "Metadata files should contain [" + cachedFile + "]";
                 implicitLockedFiles.add(cachedFile);
             } else {
                 newPinnedTimestamps.add(pinnedTimestamp);
diff --git a/server/src/test/java/org/opensearch/index/remote/RemoteStoreUtilsTests.java b/server/src/test/java/org/opensearch/index/remote/RemoteStoreUtilsTests.java
index 2a7a38587198e..d134a2bad7b74 100644
--- a/server/src/test/java/org/opensearch/index/remote/RemoteStoreUtilsTests.java
+++ b/server/src/test/java/org/opensearch/index/remote/RemoteStoreUtilsTests.java
@@ -1162,6 +1162,15 @@ public void testGetPinnedTimestampLockedFilesWithCache() {
         assertEquals(0, implicitLockedFiles.size());
         assertEquals(3, metadataFilePinnedTimestampCache.size());
 
+        assertThrows(
+            AssertionError.class,
+            () -> testGetPinnedTimestampLockedFilesWithPinnedTimestamps(
+                List.of(2000L, 2200L, 3001L, 4200L, 4600L, 5010L),
+                Set.of(3000L, 4000L, 5000L, 6000L),
+                metadataFilePinnedTimestampCache
+            )
+        );
+
         metadataAndLocks = testGetPinnedTimestampLockedFilesWithPinnedTimestamps(
             List.of(2000L, 2200L, 2500L, 3001L, 4200L, 4600L, 5010L),
             Set.of(),