the command "bitcoin-cli getblockstats 0000000000000000000c61ff8f761ce509fc8901d3c22d61fec89637042ea2ba" does not work.

It displays "error: Error parsing JSON:0000000000000000000c61ff8f761ce509fc8901d3c22d61fec89637042ea2ba"

but it should display the block stats like the documentation says.

also bitcoin-cli getblockstats 0 does not work. block number must be at least 1 to work. But blocks start at 0.

tested with 0.20.1 on freebsd, another user on IRC acknowledged the problem.
int64_t total_weight = 0;
    int64_t utxo_size_inc = 0;
    std::vector<CAmount> fee_array;
    std::vector<std::pair<CAmount, int64_t>> feerate_array;
    std::vector<int64_t> txsize_array;
    for (size_t i = 0; i < block.vtx.size(); ++i) {
        const auto& tx = block.vtx.at(i);
        outputs += tx->vout.size();
        CAmount tx_total_out = 0;
        if (loop_outputs) {
            for (const CTxOut& out : tx->vout) {
                tx_total_out += out.nValue;
                utxo_size_inc += GetSerializeSize(out, PROTOCOL_VERSION) + PER_UTXO_OVERHEAD;
            }
        }
        if (tx->IsCoinBase()) {
            continue;
        }
        inputs += tx->vin.size(); 
        total_out += tx_total_out; 
        int64_t tx_size = 0;
        if (do_calculate_size) {
            tx_size = tx->GetTotalSize();
            if (do_mediantxsize) {
                txsize_array.push_back(tx_size);
            }
            maxtxsize = std::max(maxtxsize, tx_size);
            mintxsize = std::min(mintxsize, tx_size);
            total_size += tx_size;
        }