javascript – bitcoinjs – mandatory-script-verify-flag-failed (Signature must be zero for failed CHECK(MULTI)SIG operation)

I’m trying to follow the below transaction example by magic eden and extend it to support multiple buyers and seller (in red). However I am having difficulties when I add more than one signature from another party (with one seller it broadcasts okay). The transaction builds and signs fine but when I try to broadcast it to the network it results in the error mandatory-script-verify-flag-failed (Signature must be zero for failed CHECK(MULTI)SIG operation). Using native segwit addresses for this (no-tr).

What am I missing or doing wrong?

Using the bitcoinjs library here is what I have so far (only the red):

Seller signing:

let psbt = new bitcoin.Psbt({ network });

const [ordinalUtxoTxId, ordinalUtxoVout] = ordinalOutput.split(":");
const tx = bitcoin.Transaction.fromHex(await getTxHexById(ordinalUtxoTxId));

try {
    tx.setWitness(parseInt(ordinalUtxoVout), []);
} catch {}

const input = {
  hash: ordinalUtxoTxId,
  index: parseInt(ordinalUtxoVout),
  nonWitnessUtxo: tx.toBuffer(),
  witnessUtxo: tx.outs[ordinalUtxoVout],
  sighashType:
    bitcoin.Transaction.SIGHASH_SINGLE |
    bitcoin.Transaction.SIGHASH_ANYONECANPAY,
};

psbt.addInput(input);

psbt.addOutput({
  address: paymentAddress,
  value: price,
});

Buyer Signing (ignoring padding inputs and outputs):

// Add inscriptions inputs and outputs
for (const signedPsbt of sellerSignedPsbts) {
    // Add inscription output
    psbt.addOutput({
        address: receiverAddress,
        value: signedPsbt.data.inputs[0].witnessUtxo.value,
    });

    // Add payer signed input
    psbt.addInput({
        ...signedPsbt.data.globalMap.unsignedTx.tx.ins[0],
        // ...signedPsbt.data.inputs[0],
        witnessUtxo: signedPsbt.data.inputs[0].witnessUtxo,
        nonWitnessUtxo: signedPsbt.data.inputs[0].nonWitnessUtxo,
        // finalScriptWitness: signedPsbt.data.inputs[0].finalScriptWitness,
    });

    input++;
}

// Add seller payment outputs for payee
for (const signedPsbt of sellerSignedPsbts) {
    // Add payer output
    psbt.addOutput({
        ...signedPsbt.data.globalMap.unsignedTx.tx.outs[0],
    });
}

Merge seller and buyer signed psbts:

const buyerSignedPsbt = bitcoin.Psbt.fromBase64(signedBuyingPSBTBase64);

for (let index = 0; index < signedListingsPSBTBase64.length; index++) {
    const sellerSignedPsbt = bitcoin.Psbt.fromBase64(signedListingsPSBTBase64[index]);

    buyerSignedPsbt.data.globalMap.unsignedTx.tx.ins[BUYING_PSBT_SELLER_SIGNATURE_INDEX + index] = sellerSignedPsbt.data.globalMap.unsignedTx.tx.ins[0];
    buyerSignedPsbt.data.inputs[BUYING_PSBT_SELLER_SIGNATURE_INDEX + index] = sellerSignedPsbt.data.inputs[0];
}

// broadcast buyerSignedPsbt