bitcoind `listunspenttransactions` throws "Wallet file not specified" error

I am using btcd rpcClient. In a nutshell, what I am doing, is loading a wallet, listing unspent tx and then unloading the wallet.
Here is a sample code:

import (
    "github.com/btcsuite/btcd/rpcclient"
)

connCfg := &rpcclient.ConnConfig{
    Host:         "url:port",
    User:         "username",
    Pass:         "password",
    HTTPPostMode: true, // Bitcoin core only supports HTTP POST mode
    DisableTLS:   true, // Bitcoin core does not provide TLS by default,
}

client, err := rpcclient.New(connCfg, nil)
if err != nil {
    return nil, err
}

_, _ := btcClient.LoadWallet("walletname")

_, err := btcClient.ListUnspent()

fmt.Println(err)

btcClient.UnloadWallet(&farmName)

This worked completely fine on a signet node. After that I try it on a mainnet node (seemingly with the same configuration, same node version and same method of creating the wallet) and I get the following error:
`"code":-19,"message":"Wallet file not specified (must request wallet RPC through /wallet/<filename> uri-path)."

I tried reproducing tge problem with curl and again, on the signet node this works, but on mainet node, I get the same error:

curl --user user:password --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "loadwallet", "params": ["walletname"] }' -H 'content-type: text/plain;' http://url:port/

curl --user user:password --data-binary '{"jsonrpc": "1.0", "id": "curltest", "method": "listunspent"}' -H 'content-type: text/plain;' http://url:port/

curl --user user:password --data-binary '{"jsonrpc": "1.0", "id":"curltest", "method": "unloadwallet", "params": ["walletname"] }' -H 'content-type: text/plain;' http://url:port/

Responses I get:

{"result":{"name":"walletname","warning":""},"error":null,"id":"curltest"}

{"result":null,"error":{"code":-19,"message":"Wallet file not specified (must request wallet RPC through /wallet/<filename> uri-path)."},"id":"curltest"}

{"result":{"warning":""},"error":null,"id":"curltest"}

The problem was that there was a wallet that was loading by default on the bitcoin daemon startup. When I was loading the wallet that I wanted to work with, the loaded wallet count was becoming equal to 2. When the RPC queries are done without a specified wallet, they try to use the loaded wallet, but only if the loaded wallet is only one. Since I had 2 loaded wallets, it wanted me to specify which one to use.

On the signed node, the default wallet was not loading for some reason and that is why I wasn't getting the same problem there.

One can check the loaded wallets with the listwallets method.