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.
{
    CCoinsStats stats{block_index.nHeight, block_index.GetBlockHash()};
    stats.index_used = true;
    DBVal entry;
    if (!LookUpOne(*m_db, {block_index.GetBlockHash(), block_index.nHeight}, entry)) {
        return std::nullopt;
    }
    stats.hashSerialized = entry.muhash;
    stats.nTransactionOutputs = entry.transaction_output_count;
    stats.nBogoSize = entry.bogo_size;
    stats.total_amount = entry.total_amount;
    stats.total_subsidy = entry.total_subsidy;
    stats.total_unspendable_amount = entry.total_unspendable_amount;
    stats.total_prevout_spent_amount = entry.total_prevout_spent_amount;
    stats.total_new_outputs_ex_coinbase_amount = entry.total_new_outputs_ex_coinbase_amount;
    stats.total_coinbase_amount = entry.total_coinbase_amount;
    stats.total_unspendables_genesis_block = entry.total_unspendables_genesis_block;
    stats.total_unspendables_bip30 = entry.total_unspendables_bip30;
    stats.total_unspendables_scripts = entry.total_unspendables_scripts;
    stats.total_unspendables_unclaimed_rewards = entry.total_unspendables_unclaimed_rewards;
    return stats;
}
bool CoinStatsIndex::CustomInit(const std::optional<interfaces::BlockKey>& block)