diff --git a/backend/src/api/common.ts b/backend/src/api/common.ts
index a2a74e907..37b09a417 100644
--- a/backend/src/api/common.ts
+++ b/backend/src/api/common.ts
@@ -77,10 +77,10 @@ export class Common {
     return matches;
   }
 
-  static findMinedRbfTransactions(minedTransactions: TransactionExtended[], spendMap: Map<string, TransactionExtended>): { [txid: string]: { replaced: TransactionExtended[], replacedBy: TransactionExtended }} {
-    const matches: { [txid: string]: { replaced: TransactionExtended[], replacedBy: TransactionExtended }} = {};
+  static findMinedRbfTransactions(minedTransactions: TransactionExtended[], spendMap: Map<string, MempoolTransactionExtended>): { [txid: string]: { replaced: MempoolTransactionExtended[], replacedBy: TransactionExtended }} {
+    const matches: { [txid: string]: { replaced: MempoolTransactionExtended[], replacedBy: TransactionExtended }} = {};
     for (const tx of minedTransactions) {
-      const replaced: Set<TransactionExtended> = new Set();
+      const replaced: Set<MempoolTransactionExtended> = new Set();
       for (let i = 0; i < tx.vin.length; i++) {
         const vin = tx.vin[i];
         const match = spendMap.get(`${vin.txid}:${vin.vout}`);
diff --git a/backend/src/api/mempool.ts b/backend/src/api/mempool.ts
index b5a565334..e3543f4fc 100644
--- a/backend/src/api/mempool.ts
+++ b/backend/src/api/mempool.ts
@@ -1,6 +1,6 @@
 import config from '../config';
 import bitcoinApi from './bitcoin/bitcoin-api-factory';
-import { MempoolTransactionExtended, VbytesPerSecond } from '../mempool.interfaces';
+import { MempoolTransactionExtended, TransactionExtended, VbytesPerSecond } from '../mempool.interfaces';
 import logger from '../logger';
 import { Common } from './common';
 import transactionUtils from './transaction-utils';
@@ -287,11 +287,11 @@ class Mempool {
     }
   }
 
-  public handleMinedRbfTransactions(rbfTransactions: { [txid: string]: { replaced: MempoolTransactionExtended[], replacedBy: MempoolTransactionExtended }}): void {
+  public handleMinedRbfTransactions(rbfTransactions: { [txid: string]: { replaced: MempoolTransactionExtended[], replacedBy: TransactionExtended }}): void {
     for (const rbfTransaction in rbfTransactions) {
       if (rbfTransactions[rbfTransaction].replacedBy && rbfTransactions[rbfTransaction]?.replaced?.length) {
         // Store replaced transactions
-        rbfCache.add(rbfTransactions[rbfTransaction].replaced, rbfTransactions[rbfTransaction].replacedBy);
+        rbfCache.add(rbfTransactions[rbfTransaction].replaced, transactionUtils.extendMempoolTransaction(rbfTransactions[rbfTransaction].replacedBy));
       }
     }
   }
@@ -304,7 +304,7 @@ class Mempool {
     }
   }
 
-  public removeFromSpendMap(transactions: MempoolTransactionExtended[]): void {
+  public removeFromSpendMap(transactions: TransactionExtended[]): void {
     for (const tx of transactions) {
       for (const vin of tx.vin) {
         const key = `${vin.txid}:${vin.vout}`;