diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index f6919a69d..a71e0fb0c 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -28,6 +28,7 @@ The following tip changes can be tested by building VictoriaMetrics components f
 * BUGFIX: [vmagent](https://docs.victoriametrics.com/vmagent.html): consistently put the scrape url with scrape target labels to all error logs for failed scrapes. Previously some failed scrapes were logged without this information.
 * BUGFIX: [vmagent](https://docs.victoriametrics.com/vmagent.html): do not send stale markers to remote storage for series exceeding the configured [series limit](https://docs.victoriametrics.com/vmagent.html#cardinality-limiter). See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3660).
 * BUGFIX: [vmagent](https://docs.victoriametrics.com/vmagent.html): properly apply [series limit](https://docs.victoriametrics.com/vmagent.html#cardinality-limiter) when [staleness tracking](https://docs.victoriametrics.com/vmagent.html#prometheus-staleness-markers) is disabled.
+* BUGFIX: [vmagent](https://docs.victoriametrics.com/vmagent.html): reduce memory usage spikes when big number of scrape targets disappear at once. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3668). Thanks to @lzfhust for [the initial fix](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/3669).
 * BUGFIX: [Pushgateway import](https://docs.victoriametrics.com/#how-to-import-data-in-prometheus-exposition-format): properly return `200 OK` HTTP response code. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3636).
 * BUGFIX: [MetricsQL](https://docs.victoriametrics.com/MetricsQL.html): properly parse `M` and `Mi` suffixes as `1e6` multipliers in `1M` and `1Mi` numeric constants. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3664). The issue has been introduced in [v1.86.0](https://docs.victoriametrics.com/CHANGELOG.html#v1860).
 * BUGFIX: [vmui](https://docs.victoriametrics.com/#vmui): properly display range query results at `Table` view. For example, `up[5m]` query now shows all the raw samples for the last 5 minutes for the `up` metric at the `Table` view. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3516).
diff --git a/lib/promscrape/scrapework.go b/lib/promscrape/scrapework.go
index 095138b0b..18ddb3905 100644
--- a/lib/promscrape/scrapework.go
+++ b/lib/promscrape/scrapework.go
@@ -431,15 +431,15 @@ func (sw *scrapeWork) scrapeInternal(scrapeTimestamp, realTimestamp int64) error
 	return err
 }
 
-var concurrencyLimitCh = make(chan struct{}, cgroup.AvailableCPUs())
+var processScrapedDataConcurrencyLimitCh = make(chan struct{}, cgroup.AvailableCPUs())
 
 func (sw *scrapeWork) processScrapedData(scrapeTimestamp, realTimestamp int64, body *bytesutil.ByteBuffer, err error) (bool, error) {
 	// This function is CPU-bound, while it may allocate big amounts of memory.
 	// That's why it is a good idea to limit the number of concurrent calls to this function
 	// in order to limit memory usage under high load without sacrificing the performance.
-	concurrencyLimitCh <- struct{}{}
+	processScrapedDataConcurrencyLimitCh <- struct{}{}
 	defer func() {
-		<-concurrencyLimitCh
+		<-processScrapedDataConcurrencyLimitCh
 	}()
 
 	endTimestamp := time.Now().UnixNano() / 1e6
@@ -765,7 +765,17 @@ func (sw *scrapeWork) applySeriesLimit(wc *writeRequestCtx) int {
 	return samplesDropped
 }
 
+var sendStaleSeriesConcurrencyLimitCh = make(chan struct{}, cgroup.AvailableCPUs())
+
 func (sw *scrapeWork) sendStaleSeries(lastScrape, currScrape string, timestamp int64, addAutoSeries bool) {
+	// This function is CPU-bound, while it may allocate big amounts of memory.
+	// That's why it is a good idea to limit the number of concurrent calls to this function
+	// in order to limit memory usage under high load without sacrificing the performance.
+	// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3668
+	sendStaleSeriesConcurrencyLimitCh <- struct{}{}
+	defer func() {
+		<-sendStaleSeriesConcurrencyLimitCh
+	}()
 	if sw.Config.NoStaleMarkers {
 		return
 	}
@@ -773,7 +783,11 @@ func (sw *scrapeWork) sendStaleSeries(lastScrape, currScrape string, timestamp i
 	if currScrape != "" {
 		bodyString = parser.GetRowsDiff(lastScrape, currScrape)
 	}
-        wc := writeRequestCtxPool.Get(sw.prevLabelsLen)
+	wc := writeRequestCtxPool.Get(sw.prevLabelsLen)
+	defer func() {
+		wc.reset()
+		writeRequestCtxPool.Put(wc)
+	}()
 	if bodyString != "" {
 		wc.rows.UnmarshalWithErrLogger(bodyString, sw.logError)
 		srcRows := wc.rows.Rows
@@ -805,8 +819,6 @@ func (sw *scrapeWork) sendStaleSeries(lastScrape, currScrape string, timestamp i
 		staleSamplesCreated.Add(len(samples))
 	}
 	sw.pushData(sw.Config.AuthToken, &wc.writeRequest)
-        wc.reset()
-	writeRequestCtxPool.Put(wc)
 }
 
 var staleSamplesCreated = metrics.NewCounter(`vm_promscrape_stale_samples_created_total`)