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.
EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
    bool ConnectBlock(const CBlock& block, BlockValidationState& state, CBlockIndex* pindex,
                      CCoinsViewCache& view, bool fJustCheck = false) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    
    bool DisconnectTip(BlockValidationState& state, DisconnectedBlockTransactions* disconnectpool) EXCLUSIVE_LOCKS_REQUIRED(cs_main, m_mempool->cs);
    
    /** Mark a block as precious and reorganize.
     *
     * May not be called in a validationinterface callback.
     */
    bool PreciousBlock(BlockValidationState& state, CBlockIndex* pindex)
        EXCLUSIVE_LOCKS_REQUIRED(!m_chainstate_mutex)
        LOCKS_EXCLUDED(::cs_main);
    
    bool InvalidateBlock(BlockValidationState& state, CBlockIndex* pindex)
        EXCLUSIVE_LOCKS_REQUIRED(!m_chainstate_mutex)
        LOCKS_EXCLUDED(::cs_main);
    
    void ResetBlockFailureFlags(CBlockIndex* pindex) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    
    bool ReplayBlocks();
    
    [[nodiscard]] bool NeedsRedownload() const EXCLUSIVE_LOCKS_REQUIRED(cs_main);
    
    bool LoadGenesisBlock();
    void PruneBlockIndexCandidates();
    void UnloadBlockIndex() EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
    
    bool IsInitialBlockDownload() const;