diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4306f74882..a56ecbb6f3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,7 @@
 * BUGFIX: vmagent: properly handle OpenStack endpoint ending with `v3.0` such as `https://ostack.example.com:5000/v3.0`
   in the same way as Prometheus does. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/728#issuecomment-709914803
 * BUGFIX: drop trailing data points for time series with a single raw sample. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/748
+* BUGFIX: do not drop trailing data points for instant queries to `/api/v1/query`. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/845
 * BUGFIX: vmbackup: fix panic when `-origin` isn't specified. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/856
 * BUGFIX: vmalert: skip automatically added labels on alerts restore. Label `alertgroup` was introduced in [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/611)
   and automatically added to generated time series. By mistake, this new label wasn't correctly purged on restore event and affected alert's ID uniqueness.
diff --git a/app/vmselect/promql/rollup.go b/app/vmselect/promql/rollup.go
index 41ca13b958..750550e258 100644
--- a/app/vmselect/promql/rollup.go
+++ b/app/vmselect/promql/rollup.go
@@ -519,12 +519,13 @@ func (rc *rollupConfig) doInternal(dstValues []float64, tsm *timeseriesMap, valu
 		}
 		rfa.values = values[i:j]
 		rfa.timestamps = timestamps[i:j]
-		if j == len(timestamps) && j > 0 && (tEnd-timestamps[j-1] > stalenessInterval || i == j && len(timestamps) == 1) {
+		if j == len(timestamps) && j > 0 && (tEnd-timestamps[j-1] > stalenessInterval || i == j && len(timestamps) == 1) && rc.End - tEnd >= 2*rc.Step {
 			// Drop trailing data points in the following cases:
 			// - if the distance between the last raw sample and tEnd exceeds stalenessInterval
 			// - if time series contains only a single raw sample
 			// This should prevent from double counting when a label changes in time series (for instance,
 			// during new deployment in K8S). See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/748
+			// Do not drop trailing data points for instant queries. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/845
 			rfa.prevValue = nan
 			rfa.values = nil
 			rfa.timestamps = nil