diff --git a/app/vmselect/promql/rollup.go b/app/vmselect/promql/rollup.go
index 5a2cde4be1..6099b58c83 100644
--- a/app/vmselect/promql/rollup.go
+++ b/app/vmselect/promql/rollup.go
@@ -234,7 +234,7 @@ func getMaxPrevInterval(timestamps []int64) int64 {
 		return 1
 	}
 	// Slightly increase d in order to handle possible jitter in scrape interval.
-	return d + (d / 8)
+	return d + (d / 4)
 }
 
 func removeCounterResets(values []float64) {
diff --git a/app/vmselect/promql/rollup_test.go b/app/vmselect/promql/rollup_test.go
index e5b621fb98..fdb79c8d37 100644
--- a/app/vmselect/promql/rollup_test.go
+++ b/app/vmselect/promql/rollup_test.go
@@ -454,7 +454,7 @@ func TestRollupWindowPartialPoints(t *testing.T) {
 		}
 		rc.Timestamps = getTimestamps(rc.Start, rc.End, rc.Step)
 		values := rc.Do(nil, testValues, testTimestamps)
-		valuesExpected := []float64{44, 34, 34, nan}
+		valuesExpected := []float64{44, 34, 34, 34}
 		timestampsExpected := []int64{100, 120, 140, 160}
 		testRowsEqual(t, values, rc.Timestamps, valuesExpected, timestampsExpected)
 	})