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.
const std::string& index_name,
                                       int start_height, int stop_height)
{
    DBHeightKey key{start_height};
    db_it.Seek(key);
    for (int height = start_height; height <= stop_height; ++height) {
        if (!db_it.GetKey(key) || key.height != height) {
            return error("%s: unexpected key in %s: expected (%c, %d)",
                         __func__, index_name, DB_BLOCK_HEIGHT, height);
        }
        std::pair<uint256, DBVal> value;
        if (!db_it.GetValue(value)) {
            return error("%s: unable to read value in %s at key (%c, %d)",
                         __func__, index_name, DB_BLOCK_HEIGHT, height);
        }
        batch.Write(DBHashKey(value.first), std::move(value.second));
        db_it.Next();
    }
    return true;
}
bool CoinStatsIndex::CustomRewind(const interfaces::BlockKey& current_tip, const interfaces::BlockKey& new_tip)