When the newly introduced `"maxfeerate"` option is not passed, the default fee rate is interpreted as an absolute amount. However, when it is passed, it is interpreted as a fee rate. Thus, the rpc will return different results when the value is explicitly set to the default.

See

https://github.com/bitcoin/bitcoin/blob/536590f358dc3d3e5821eba7f1009452ea93b205/src/rpc/rawtransaction.cpp#L797-L807

I think we should change it back to an absolute value in BTC (not a feerate)

This was changed to a feerate by @kallewoof, so ping him to see if there was a specific reason to switch.
CAmount output_value = 0;
    UniValue outputs(UniValue::VARR);
    for (unsigned int i = 0; i < psbtx.outputs.size(); ++i) {
        const PSBTOutput& output = psbtx.outputs[i];
        UniValue out(UniValue::VOBJ);
        
        if (!output.redeem_script.empty()) {
            UniValue r(UniValue::VOBJ);
            ScriptToUniv(output.redeem_script, r, false);
            out.pushKV("redeem_script", r);
        }
        if (!output.witness_script.empty()) {
            UniValue r(UniValue::VOBJ);
            ScriptToUniv(output.witness_script, r, false);
            out.pushKV("witness_script", r);
        }
        
        if (!output.hd_keypaths.empty()) {
            UniValue keypaths(UniValue::VARR);
            for (auto entry : output.hd_keypaths) {
                UniValue keypath(UniValue::VOBJ);
                keypath.pushKV("pubkey", HexStr(entry.first));
                keypath.pushKV("master_fingerprint", strprintf("%08x", ReadBE32(entry.second.fingerprint)));
                keypath.pushKV("path", WriteHDKeypath(entry.second.path));
                keypaths.push_back(keypath);
            }
            out.pushKV("bip32_derivs", keypaths);
        }
        
        if (output.unknown.size() > 0) {