diff --git a/ledger/src/blockstore.rs b/ledger/src/blockstore.rs
index a0d5102bba19d4..01f6fcd6b4ffa6 100644
--- a/ledger/src/blockstore.rs
+++ b/ledger/src/blockstore.rs
@@ -41,6 +41,7 @@ use solana_transaction_status::{
     TransactionStatusMeta, TransactionWithStatusMeta,
 };
 use std::{
+    borrow::Cow,
     cell::RefCell,
     cmp,
     collections::{HashMap, HashSet},
@@ -1187,6 +1188,7 @@ impl Blockstore {
             } else if !self.should_insert_data_shred(
                 &shred,
                 slot_meta,
+                just_inserted_data_shreds,
                 &self.last_root,
                 leader_schedule,
                 is_recovered,
@@ -1258,10 +1260,26 @@ impl Blockstore {
         shred_index < slot_meta.consumed || data_index.is_present(shred_index)
     }
 
+    fn get_data_shred_from_just_inserted_or_db<'a>(
+        &'a self,
+        just_inserted_data_shreds: &'a HashMap<(u64, u64), Shred>,
+        slot: Slot,
+        index: u64,
+    ) -> Cow<'a, Vec<u8>> {
+        if let Some(shred) = just_inserted_data_shreds.get(&(slot, index)) {
+            Cow::Borrowed(&shred.payload)
+        } else {
+            // If it doesn't exist in the just inserted set, it must exist in
+            // the backing store
+            Cow::Owned(self.get_data_shred(slot, index).unwrap().unwrap())
+        }
+    }
+
     fn should_insert_data_shred(
         &self,
         shred: &Shred,
         slot_meta: &SlotMeta,
+        just_inserted_data_shreds: &HashMap<(u64, u64), Shred>,
         last_root: &RwLock<u64>,
         leader_schedule: Option<&Arc<LeaderScheduleCache>>,
         is_recovered: bool,
@@ -1283,25 +1301,34 @@ impl Blockstore {
                 .map(|leader_schedule| leader_schedule.slot_leader_at(slot, None))
                 .unwrap_or(None);
 
-            let ending_shred = self.get_data_shred(slot, last_index).unwrap().unwrap();
+            let ending_shred: Cow<Vec<u8>> = self.get_data_shred_from_just_inserted_or_db(
+                just_inserted_data_shreds,
+                slot,
+                last_index,
+            );
+
             if self
-                .store_duplicate_if_not_existing(slot, ending_shred, shred.payload.clone())
+                .store_duplicate_if_not_existing(
+                    slot,
+                    ending_shred.into_owned(),
+                    shred.payload.clone(),
+                )
                 .is_err()
             {
                 warn!("store duplicate error");
             }
 
             datapoint_error!(
-                "blockstore_error",
-                (
-                    "error",
-                    format!(
-                        "Leader {:?}, slot {}: received index {} >= slot.last_index {}, is_recovered: {}",
-                        leader_pubkey, slot, shred_index, last_index, is_recovered
-                    ),
-                    String
-                )
-            );
+                    "blockstore_error",
+                    (
+                        "error",
+                        format!(
+                            "Leader {:?}, slot {}: received index {} >= slot.last_index {}, is_recovered: {}",
+                            leader_pubkey, slot, shred_index, last_index, is_recovered
+                        ),
+                        String
+                    )
+                );
             return false;
         }
         // Check that we do not receive a shred with "last_index" true, but shred_index
@@ -1311,28 +1338,34 @@ impl Blockstore {
                 .map(|leader_schedule| leader_schedule.slot_leader_at(slot, None))
                 .unwrap_or(None);
 
-            let ending_shred = self
-                .get_data_shred(slot, slot_meta.received - 1)
-                .unwrap()
-                .unwrap();
+            let ending_shred: Cow<Vec<u8>> = self.get_data_shred_from_just_inserted_or_db(
+                just_inserted_data_shreds,
+                slot,
+                slot_meta.received - 1,
+            );
+
             if self
-                .store_duplicate_if_not_existing(slot, ending_shred, shred.payload.clone())
+                .store_duplicate_if_not_existing(
+                    slot,
+                    ending_shred.into_owned(),
+                    shred.payload.clone(),
+                )
                 .is_err()
             {
                 warn!("store duplicate error");
             }
 
             datapoint_error!(
-                "blockstore_error",
-                (
-                    "error",
-                    format!(
-                        "Leader {:?}, slot {}: received shred_index {} < slot.received {}, is_recovered: {}",
-                        leader_pubkey, slot, shred_index, slot_meta.received, is_recovered
-                    ),
-                    String
-                )
-            );
+                    "blockstore_error",
+                    (
+                        "error",
+                        format!(
+                            "Leader {:?}, slot {}: received shred_index {} < slot.received {}, is_recovered: {}",
+                            leader_pubkey, slot, shred_index, slot_meta.received, is_recovered
+                        ),
+                        String
+                    )
+                );
             return false;
         }
 
@@ -5165,7 +5198,14 @@ pub mod tests {
                 }
             };
             assert_eq!(
-                blockstore.should_insert_data_shred(&shred7, &slot_meta, &last_root, None, false),
+                blockstore.should_insert_data_shred(
+                    &shred7,
+                    &slot_meta,
+                    &HashMap::new(),
+                    &last_root,
+                    None,
+                    false
+                ),
                 false
             );
             assert!(blockstore.has_duplicate_shreds_in_slot(0));
@@ -5182,7 +5222,14 @@ pub mod tests {
                 panic!("Shred in unexpected format")
             }
             assert_eq!(
-                blockstore.should_insert_data_shred(&shred7, &slot_meta, &last_root, None, false),
+                blockstore.should_insert_data_shred(
+                    &shred7,
+                    &slot_meta,
+                    &HashMap::new(),
+                    &last_root,
+                    None,
+                    false
+                ),
                 false
             );
         }
@@ -7447,4 +7494,24 @@ pub mod tests {
         }
         Blockstore::destroy(&blockstore_path).expect("Expected successful database destruction");
     }
+
+    #[test]
+    fn test_duplicate_last_index() {
+        let num_shreds = 2;
+        let num_entries = max_ticks_per_n_shreds(num_shreds, None);
+        let slot = 1;
+        let (mut shreds, _) = make_slot_entries(slot, 0, num_entries);
+
+        // Mark both as last shred
+        shreds[0].set_last_in_slot();
+        shreds[1].set_last_in_slot();
+        let blockstore_path = get_tmp_ledger_path!();
+        {
+            let blockstore = Blockstore::open(&blockstore_path).unwrap();
+            blockstore.insert_shreds(shreds, None, false).unwrap();
+
+            assert!(blockstore.get_duplicate_slot(slot).is_some());
+        }
+        Blockstore::destroy(&blockstore_path).expect("Expected successful database destruction");
+    }
 }