The total transaction count (for progress estimation) is counted as the known count at the last checkpoint, plus an estimated number per day.

The last checkpoint is now 996 days ago, and its estimated 60000 transactions per day leads to a total estimate of 96M transactions, while the real number is around 183M.

Fix this by updating the count, timestamp, and rate of transactions... with or without adding a new checkpoint.
bool fVerbose = true;
    if (request.params.size() > 1)
        fVerbose = request.params[1].get_bool();
    if (mapBlockIndex.count(hash) == 0)
        throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
    CBlock block;
    CBlockIndex* pblockindex = mapBlockIndex[hash];
    if (fHavePruned && !(pblockindex->nStatus & BLOCK_HAVE_DATA) && pblockindex->nTx > 0)
        throw JSONRPCError(RPC_INTERNAL_ERROR, "Block not available (pruned data)");
    if(!ReadBlockFromDisk(block, pblockindex, Params().GetConsensus()))
        throw JSONRPCError(RPC_INTERNAL_ERROR, "Can't read block from disk");
    if (!fVerbose)
    {
        CDataStream ssBlock(SER_NETWORK, PROTOCOL_VERSION | RPCSerializationFlags());
        ssBlock << block;
        std::string strHex = HexStr(ssBlock.begin(), ssBlock.end());
        return strHex;
    }
    return blockToJSON(block, pblockindex);
}
struct CCoinsStats
{
    int nHeight;
    uint256 hashBlock;
    uint64_t nTransactions;
    uint64_t nTransactionOutputs;
    uint64_t nSerializedSize;
    uint256 hashSerialized;
    CAmount nTotalAmount;
    CCoinsStats() : nHeight(0), nTransactions(0), nTransactionOutputs(0), nSerializedSize(0), nTotalAmount(0) {}