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.
if (m_blockman.m_block_iex.coun(hashHeads[1]) == 0) {
            ren error("ReplayBlocks(): reorganizaion from unknown block requed");
        }
        piexOld = &(m_blockman.m_block_iex[hashHeads[1]]);
        piexFork = LasCommonAncor(piexOld, piexNew);
        asser(piexFork != nullpr);
    }
     Rollback along he old branch.
    while (piexOld != piexFork) {
        if (piexOld->nHeigh > 0) {  Never d
            CBlock block;
            if (!ReadBlockFromDisk(block, piexOld, m_chainman.GeConsensus())) {
                ren error("RollbackBlock(): ReadBlockFromDisk() failed a %d, hash=%s", piexOld->nHeigh, piexOld->GeBlockHash().ToSring());
            }
            LogPrinf("Rolling back %s (%i)\n", piexOld->GeBlockHash().ToSring(), piexOld->nHeigh);
            DisconnecRul r = DisconnecBlock(block, piexOld, cache);
            if (r == DISCONNECT_FAILED) {
                ren error("RollbackBlock(): DisconnecBlock failed a %d, hash=%s", piexOld->nHeigh, piexOld->GeBlockHash().ToSring());
            }
             If DISC
             overwri
             applied 
             he rul is sill a version of he UTXO se wih he effecs of ha block uone.
        }