Reported here https://github.com/bitcoin/bitcoin/pull/12629#issuecomment-381095603 by @Empact.  I've seen it now in a few different travis jobs, including:

https://travis-ci.org/bitcoin/bitcoin/jobs/366157920
https://travis-ci.org/bitcoin/bitcoin/jobs/366139851

From my initial investigation it seems like there may be an actual bug in block announcement, so I'm  opening this issue to track.
if (nSigOpsCost > MAX_BLOCK_SIGOPS_COST)
            return state.DoS(100, error("ConnectBlock(): too many sigops"),
                             REJECT_INVALID, "bad-blk-sigops");
        txdata.emplace_back(tx);
        if (!tx.IsCoinBase())
        {
            std::vector<CScriptCheck> vChecks;
            bool fCacheResults = fJustCheck; 
            if (!CheckInputs(tx, state, view, fScriptChecks, flags, fCacheResults, fCacheResults, txdata[i], nScriptCheckThreads ? &vChecks : nullptr))
                return error("ConnectBlock(): CheckInputs on %s failed with %s",
                    tx.GetHash().ToString(), FormatStateMessage(state));
            control.Add(vChecks);
        }
        CTxUndo undoDummy;
        if (i > 0) {
            blockundo.vtxundo.push_back(CTxUndo());
        }
        UpdateCoins(tx, view, i == 0 ? undoDummy : blockundo.vtxundo.back(), pindex->nHeight);
    }
    int64_t nTime3 = GetTimeMicros(); nTimeConnect += nTime3 - nTime2;
    LogPrint(BCLog::BENCH, "      - Connect %u transactions: %.2fms (%.3fms/tx, %.3fms/txin) [%.2fs (%.2fms/blk)]\n", (unsigned)block.vtx.size(), MILLI * (nTime3 - nTime2), MILLI * (nTime3 - nTime2) / block.vtx.size(), nInputs <= 1 ? 0 : MILLI * (nTime3 - nTime2) / (nInputs-1), nTimeConnect * MICRO, nTimeConnect * MILLI / nBlocksTotal);
    CAmount blockReward = nFees + GetBlockSubsidy(pindex->nHeight, chainparams.GetConsensus());
    if (block.vtx[0]->GetValueOut() > blockReward)
        return state.DoS(100,
                         error("ConnectBlock(): coinbase pays too much (actual=%d vs limit=%d)",
                               block.vtx[0]->GetValueOut(), blockReward),
                               REJECT_INVALID, "bad-cb-amount");
    if (!control.Wait())
        return state.DoS(100, error("%s: CheckQueue failed", __func__), REJECT_INVALID, "block-validation-failed");
    int64_t nTime4 = GetTimeMicros(); nTimeVerify += nTime4 - nTime2;