When I run `scantxoutset` via RPC using big range (e.g. 10000) on XPUB, the progress report indicator (`scantxoutset status`) reports 100% at start (while the keys are being derived). This is most probably the result of the previous operation. The progress is only reset to zero when the actual scan starts. I would expect the progress is set to zero before the keys are being derived.

Output of periodic calls to `scantxoutset status` while performing long operation.

```
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 100 }
{ progress: 0 }
{ progress: 3 }
{ progress: 6 }
{ progress: 9 }
{ progress: 12 }
{ progress: 15 }
{ progress: 17 }
{ progress: 20 }
{ progress: 23 }
{ progress: 26 }
{ progress: 29 }
{ progress: 32 }
{ progress: 35 }
{ progress: 37 }
{ progress: 40 }
{ progress: 43 }
{ progress: 46 }
{ progress: 49 }
{ progress: 51 }
{ progress: 54 }
{ progress: 57 }
{ progress: 60 }
{ progress: 63 }
{ progress: 66 }
{ progress: 68 }
{ progress: 71 }
{ progress: 74 }
{ progress: 77 }
{ progress: 80 }
{ progress: 82 }
{ progress: 85 }
{ progress: 88 }
{ progress: 91 }
{ progress: 94 }
{ progress: 97 }
{ progress: 100 }
```
CAmount feerate = weight ? (txfee * WITNESS_SCALE_FACTOR) / weight : 0;
            if (do_feerate_percentiles) {
                feerate_array.emplace_back(std::make_pair(feerate, weight));
            }
            maxfeerate = std::max(maxfeerate, feerate);
            minfeerate = std::min(minfeerate, feerate);
        }
    }
    CAmount feerate_percentiles[NUM_GETBLOCKSTATS_PERCENTILES] = { 0 };
    CalculatePercentilesByWeight(feerate_percentiles, feerate_array, total_weight);
    UniValue feerates_res(UniValue::VARR);
    for (int64_t i = 0; i < NUM_GETBLOCKSTATS_PERCENTILES; i++) {
        feerates_res.push_back(feerate_percentiles[i]);
    }
    UniValue ret_all(UniValue::VOBJ);
    ret_all.pushKV("avgfee", (block.vtx.size() > 1) ? totalfee / (block.vtx.size() - 1) : 0);
    ret_all.pushKV("avgfeerate", total_weight ? (totalfee * WITNESS_SCALE_FACTOR) / total_weight : 0); 
    ret_all.pushKV("avgtxsize", (block.vtx.size() > 1) ? total_size / (block.vtx.size() - 1) : 0);
    ret_all.pushKV("blockhash", pindex->GetBlockHash().GetHex());
    ret_all.pushKV("feerate_percentiles", feerates_res);
    ret_all.pushKV("height", (int64_t)pindex->nHeight);
    ret_all.pushKV("ins", inputs);
    ret_all.pushKV("maxfee", maxfee);
    ret_all.pushKV("maxfeerate", maxfeerate);
    ret_all.pushKV("maxtxsize", maxtxsize);
    ret_all.pushKV("medianfee", CalculateTruncatedMedian(fee_array));
    ret_all.pushKV("mediantime", pindex->GetMedianTimePast());
    ret_all.pushKV("mediantxsize", CalculateTruncatedMedian(txsize_array));
    ret_all.pushKV("minfee", (minfee == MAX_MONEY) ? 0 : minfee);
    ret_all.pushKV("minfeerate", (minfeerate == MAX_MONEY) ? 0 : minfeerate);