diff --git a/tests/cases/standalone/common/promql/label.result b/tests/cases/standalone/common/promql/label.result
index 3fe8d559221..f6e169eebe3 100644
--- a/tests/cases/standalone/common/promql/label.result
+++ b/tests/cases/standalone/common/promql/label.result
@@ -484,3 +484,52 @@ DROP TABLE test;
 
 Affected Rows: 0
 
+-- Issue 9444 --
+-- Normalizing mixed histogram boundary representations must not be rejected while
+-- another label still tells the series apart.
+CREATE TABLE demo_bucket (
+  ts timestamp(3) time index,
+  instance STRING,
+  le STRING,
+  val DOUBLE,
+  PRIMARY KEY(instance, le),
+);
+
+Affected Rows: 0
+
+INSERT INTO TABLE demo_bucket VALUES
+    (3000000, 'a', '10', 40),
+    (3000000, 'a', '100', 50),
+    (3000000, 'a', '+Inf', 50),
+    (3000000, 'b', '10.0', 40),
+    (3000000, 'b', '100.0', 50),
+    (3000000, 'b', '1000.0', 50),
+    (3000000, 'b', '+Inf', 50);
+
+Affected Rows: 7
+
+-- SQLNESS SORT_RESULT 3 1
+TQL EVAL (3000, 3000, '5s') label_replace(demo_bucket, "le", "$1", "le", "([0-9]+)[.]0+");
+
++---------------------+------+------+----------+
+| ts                  | val  | le   | instance |
++---------------------+------+------+----------+
+| 1970-01-01T00:50:00 | 40.0 | 10   | a        |
+| 1970-01-01T00:50:00 | 40.0 | 10   | b        |
+| 1970-01-01T00:50:00 | 50.0 | +Inf | a        |
+| 1970-01-01T00:50:00 | 50.0 | +Inf | b        |
+| 1970-01-01T00:50:00 | 50.0 | 100  | a        |
+| 1970-01-01T00:50:00 | 50.0 | 100  | b        |
+| 1970-01-01T00:50:00 | 50.0 | 1000 | b        |
++---------------------+------+------+----------+
+
+-- Aggregating `instance` away first makes the same rewrite collapse two series into
+-- one label set, which is a genuine duplicate and must still fail.
+TQL EVAL (3000, 3000, '5s') label_replace(sum by (le) (demo_bucket), "le", "$1", "le", "([0-9]+)[.]0+");
+
+Error: 3001(EngineExecuteQuery), Execution error: vector cannot contain metrics with the same labelset
+
+DROP TABLE demo_bucket;
+
+Affected Rows: 0
+
diff --git a/tests/cases/standalone/common/promql/label.sql b/tests/cases/standalone/common/promql/label.sql
index 6c2d64d42ac..e269b6a1783 100644
--- a/tests/cases/standalone/common/promql/label.sql
+++ b/tests/cases/standalone/common/promql/label.sql
@@ -144,3 +144,32 @@ TQL EVAL (0, 1, '5s') test{job=""};
 TQL EVAL (0, 1, '5s') test{job!=""};
 
 DROP TABLE test;
+
+-- Issue 9444 --
+-- Normalizing mixed histogram boundary representations must not be rejected while
+-- another label still tells the series apart.
+CREATE TABLE demo_bucket (
+  ts timestamp(3) time index,
+  instance STRING,
+  le STRING,
+  val DOUBLE,
+  PRIMARY KEY(instance, le),
+);
+
+INSERT INTO TABLE demo_bucket VALUES
+    (3000000, 'a', '10', 40),
+    (3000000, 'a', '100', 50),
+    (3000000, 'a', '+Inf', 50),
+    (3000000, 'b', '10.0', 40),
+    (3000000, 'b', '100.0', 50),
+    (3000000, 'b', '1000.0', 50),
+    (3000000, 'b', '+Inf', 50);
+
+-- SQLNESS SORT_RESULT 3 1
+TQL EVAL (3000, 3000, '5s') label_replace(demo_bucket, "le", "$1", "le", "([0-9]+)[.]0+");
+
+-- Aggregating `instance` away first makes the same rewrite collapse two series into
+-- one label set, which is a genuine duplicate and must still fail.
+TQL EVAL (3000, 3000, '5s') label_replace(sum by (le) (demo_bucket), "le", "$1", "le", "([0-9]+)[.]0+");
+
+DROP TABLE demo_bucket;