Steps to reproduce on regtest:

```
converttopsbt 02000000000101ab73dba46508bacdb49a988ddd74bc9d39c9cb7e057af060ca8c6b6861e28e3c0300000000feffffff02b828d0b20000000017a914d1954862afd728fbb055149002958e1d1b9e1f0b8700ca9a3b0000000017a91442170ccb3441cff1723af9afab6f2553103e1d578702473044022077380c6e16496d9905aef120694c329be51522847cb5d53fa74b94698c95678d02202d32c46e0e17420a83dee830fefda7d40529182f5d82be47c2b49a7b83214ab50121026d483d6628dcc3ef6e3ab9ed4937c452c263c7e0ac80eb4be97426d5da8f640500000000
```
or 
```
converttopsbt 02000000000101ab73dba46508bacdb49a988ddd74bc9d39c9cb7e057af060ca8c6b6861e28e3c0300000000feffffff02b828d0b20000000017a914d1954862afd728fbb055149002958e1d1b9e1f0b8700ca9a3b0000000017a91442170ccb3441cff1723af9afab6f2553103e1d578702473044022077380c6e16496d9905aef120694c329be51522847cb5d53fa74b94698c95678d02202d32c46e0e17420a83dee830fefda7d40529182f5d82be47c2b49a7b83214ab50121026d483d6628dcc3ef6e3ab9ed4937c452c263c7e0ac80eb4be97426d5da8f640500000000 false
```

Further reading: #13738
bool witness_specified = !request.params[2].isNull();
    bool iswitness = witness_specified ? request.params[2].get_bool() : false;
    bool try_witness = permitsigdata ? (witness_specified ? iswitness : true) : false;
    bool try_no_witness = permitsigdata ? (witness_specified ? !iswitness : true) : true;
    if (!DecodeHexTx(tx, request.params[0].get_str(), try_no_witness, try_witness)) {
        throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX decode failed");
    }
    
    for (CTxIn& input : tx.vin) {
        if ((!input.scriptSig.empty() || !input.scriptWitness.IsNull()) && !permitsigdata) {
            throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "Inputs must not have scriptSigs and scriptWitnesses");
        }
        input.scriptSig.clear();
        input.scriptWitness.SetNull();
    }
    
    PartiallySignedTransaction psbtx;
    psbtx.tx = tx;
    for (unsigned int i = 0; i < tx.vin.size(); ++i) {
        psbtx.inputs.push_back(PSBTInput());
    }
    for (unsigned int i = 0; i < tx.vout.size(); ++i) {
        psbtx.outputs.push_back(PSBTOutput());
    }
    
    CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
    ssTx << psbtx;
    return EncodeBase64((unsigned char*)ssTx.data(), ssTx.size());
}
UniValue utxoupdatepsbt(const JSONRPCRequest& request)