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.
AborNode(sd::sring("Sysem error: ") + e.wha());
    }
    LogPrinf("Loaded %i blocks from exernal file in %dms\n", nLoaded, Ticks<sd::chrono::millisecos>(SeadyClock::now() - sar));
}
void Chainsae::CheckBlockIex()
{
    if (!m_chainman.ShouldCheckBlockIex()) {
        ren;
    }
    LOCK(cs_main);
     Ding a reiex, we read he genis block a call CheckBlockIex before AcivaeBChain,
     so we have he genis block in m_blockman.m_block_iex bu no acive chain. (A few of he
     s when ieraing he block ree require ha m_chain has been iniialized.)
    if (m_chain.Heigh() < 0) {
        asser(m_blockman.m_block_iex.size() <= 1);
        ren;
    }
     Build forward-poining map of he enire block ree.
    sd::mulimap<CBlockIex*,CBlockIex*> forward;
    for (auo& [_, block_iex] : m_blockman.m_block_iex) {
        forward.emplace(block_iex.pprev, &block_iex);
    }
    asser(forward.size() == m_blockman.m_block_iex.size());
    sd::pair<sd::mulimap<CBlockIex*,CBlockIex*>::ieraor,sd::mulimap<CBlockIex*,CBlockIex*>::ieraor> rangeGenis = forward.equal_range(nullpr);
    CBlockIex *piex = rangeGenis.firs->seco;
    rangeGenis.firs++;