diff --git a/src/app/features/psbt-signer/hooks/use-psbt-signer.tsx b/src/app/features/psbt-signer/hooks/use-psbt-signer.tsx
index f1c5cb28696..c0c2f43dbf5 100644
--- a/src/app/features/psbt-signer/hooks/use-psbt-signer.tsx
+++ b/src/app/features/psbt-signer/hooks/use-psbt-signer.tsx
@@ -40,7 +40,7 @@ export function usePsbtSigner() {
           // If type taproot, and the tapInternalKey is missing, assume it should
           // be the account publicKey
           if (taprootSigner && witnessOutputScript?.type === 'tr' && !input.tapInternalKey) {
-            input.tapInternalKey = taprootSigner.payment.tapInternalKey;
+            tx.updateInput(idx, { ...input, tapInternalKey: taprootSigner.payment.tapInternalKey });
           }
 
           try {
diff --git a/test-app/src/components/bitcoin.tsx b/test-app/src/components/bitcoin.tsx
index 72b645edba7..97e854b8b65 100644
--- a/test-app/src/components/bitcoin.tsx
+++ b/test-app/src/components/bitcoin.tsx
@@ -139,6 +139,7 @@ function buildTestTaprootPsbtRequestWithIndex(pubKey: Uint8Array): PsbtRequestOp
   tx.addInput({
     index: 0,
     txid: '4f4cc7cb40b04978bd7704798dc1adf55b58196cef616b0fac8181965abc4726',
+    // tapInternalKey: payment.tapInternalKey,
     witnessUtxo: {
       amount: BigInt(1000),
       script: payment.script,