diff --git a/src/script/sign.h b/src/script/sign.h
--- a/src/script/sign.h
+++ b/src/script/sign.h
@@ -665,7 +665,10 @@
                    CMutableTransaction &txTo, unsigned int nIn,
                    SigHashType sigHashType);
 
-/** Signs a PSBTInput */
+/**
+ * Signs a PSBTInput, verifying that all provided data matches what is being
+ * signed.
+ */
 bool SignPSBTInput(const SigningProvider &provider,
                    const CMutableTransaction &tx, PSBTInput &input,
                    SignatureData &sigdata, int index,
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -5141,10 +5141,11 @@
         // If we don't know about this input, skip it and let someone else deal
         // with it
         const TxId &txid = txin.prevout.GetTxId();
-        const auto &it = pwallet->mapWallet.find(txid);
+        const auto it = pwallet->mapWallet.find(txid);
         if (it != pwallet->mapWallet.end()) {
             const CWalletTx &wtx = it->second;
             CTxOut utxo = wtx.tx->vout[txin.prevout.GetN()];
+            // Update UTXOs from the wallet.
             input.utxo = utxo;
         }