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.
{
        return m_mempool ? &m_mempool->cs : nullptr;
    }
    /**
     * Make mempool consistent after a reorg, by re-adding or recursively erasing
     * disconnected block transactions from the mempool, and also removing any
     * other transactions from the mempool that are no longer valid given the new
     * tip/height.
     *
     * Note: we assume that disconnectpool only contains transactions that are NOT
     * confirmed in the current chain nor already in the mempool (otherwise,
     * in-mempool descendants of such transactions would be removed).
     *
     * Passing fAddToMempool=false will skip trying to add the transactions back,
     * and instead just erase from the mempool as needed.
     */
    void MaybeUpdateMempoolForReorg(
        DisconnectedBlockTransactions& disconnectpool,
        bool fAddToMempool) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool->cs);
    
    void UpdateTip(const CBlockIndex* pindexNew)
        EXCLUSIVE_LOCKS_REQUIRED(::cs_main);