diff --git a/promql/functions.go b/promql/functions.go
index aef73e7f2..a0a118c11 100644
--- a/promql/functions.go
+++ b/promql/functions.go
@@ -603,7 +603,7 @@ func funcLastOverTime(vals []parser.Value, args parser.Expressions, enh *EvalNod
 	}
 	return append(enh.Out, Sample{
 		Metric: el.Metric,
-		H:      h.H,
+		H:      h.H.Copy(),
 	}), nil
 }
 
diff --git a/promql/testdata/native_histograms.test b/promql/testdata/native_histograms.test
index b74886f73..5f0945d32 100644
--- a/promql/testdata/native_histograms.test
+++ b/promql/testdata/native_histograms.test
@@ -224,3 +224,14 @@ eval instant at 5m histogram_fraction(0, 4, balanced_histogram)
 # the first populated bucket after the span of empty buckets.
 eval instant at 5m histogram_quantile(0.5, balanced_histogram)
 	{} 0.5
+
+# Add histogram to test sum(last_over_time) regression
+load 5m
+    incr_sum_histogram{number="1"} {{schema:0 sum:0 count:0 buckets:[1]}}+{{schema:0 sum:1 count:1 buckets:[1]}}x10
+    incr_sum_histogram{number="2"} {{schema:0 sum:0 count:0 buckets:[1]}}+{{schema:0 sum:2 count:1 buckets:[1]}}x10
+
+eval instant at 50m histogram_sum(sum(incr_sum_histogram))
+    {} 30
+
+eval instant at 50m histogram_sum(sum(last_over_time(incr_sum_histogram[5m])))
+    {} 30