diff --git a/tsdb/head_read.go b/tsdb/head_read.go
index 29adc3ee74..2a25e77725 100644
--- a/tsdb/head_read.go
+++ b/tsdb/head_read.go
@@ -262,6 +262,10 @@ func unpackHeadChunkRef(ref chunks.ChunkRef) (seriesID chunks.HeadSeriesRef, chu
 	return sid, (cid & (oooChunkIDMask - 1)), (cid & oooChunkIDMask) != 0
 }
 
+func isOOOChunkID(cid chunks.HeadChunkID) bool {
+	return (cid & oooChunkIDMask) != 0
+}
+
 // LabelValueFor returns label value for the given label name in the series referred to by ID.
 func (h *headIndexReader) LabelValueFor(_ context.Context, id storage.SeriesRef, label string) (string, error) {
 	memSeries := h.head.series.getByID(chunks.HeadSeriesRef(id))
diff --git a/tsdb/ooo_head_read.go b/tsdb/ooo_head_read.go
index 26cd4d057e..78ed1c4cdc 100644
--- a/tsdb/ooo_head_read.go
+++ b/tsdb/ooo_head_read.go
@@ -146,9 +146,13 @@ func getOOOSeriesChunks(s *memSeries, mint, maxt int64, lastGarbageCollectedMmap
 	// In the example 5 overlaps with 7 and 6 overlaps with 8 so we will return
 	// [5,7], [6,8].
 	toBeMerged := tmpChks[0]
-	for _, c := range tmpChks[1:] {
-		if c.MinTime > toBeMerged.MaxTime {
-			// This chunk doesn't overlap. Send current toBeMerged to output and start a new one.
+	prevIsOOO := false
+	for i, c := range tmpChks[1:] {
+		currIsOOO := isOOOChunkID(chunks.HeadChunkID(c.Ref))
+		if c.MinTime > toBeMerged.MaxTime && (i == 0 || prevIsOOO == currIsOOO) {
+			// This chunk doesn't overlap and we are not switching between in-order
+			// and out-of-order chunks. Send current toBeMerged to output and start
+			// a new one.
 			*chks = append(*chks, toBeMerged)
 			toBeMerged = c
 		} else {
@@ -162,6 +166,7 @@ func getOOOSeriesChunks(s *memSeries, mint, maxt int64, lastGarbageCollectedMmap
 				toBeMerged.MaxTime = c.MaxTime
 			}
 		}
+		prevIsOOO = currIsOOO
 	}
 	*chks = append(*chks, toBeMerged)