diff --git a/scrape/manager_test.go b/scrape/manager_test.go
index 93970a4573..e0ba46b9d2 100644
--- a/scrape/manager_test.go
+++ b/scrape/manager_test.go
@@ -783,7 +783,8 @@ func TestManagerCTZeroIngestion(t *testing.T) {
 					// Disable regular scrapes.
 					ScrapeInterval: model.Duration(9999 * time.Minute),
 					ScrapeTimeout:  model.Duration(5 * time.Second),
-					// Ensure proto is chosen.
+					// Ensure the proto is chosen. We need proto as it's the only protocol
+					// with the CT parsing support.
 					ScrapeProtocols: []config.ScrapeProtocol{config.PrometheusProto},
 				},
 				ScrapeConfigs: []*config.ScrapeConfig{{JobName: "test"}},
diff --git a/scrape/scrape.go b/scrape/scrape.go
index 97684bd01c..be27a5d487 100644
--- a/scrape/scrape.go
+++ b/scrape/scrape.go
@@ -1574,7 +1574,7 @@ loop:
 			if err != nil && !errors.Is(err, storage.ErrOutOfOrderCT) { // OOO is a common case, ignoring completely for now.
 				// CT is an experimental feature. For now, we don't need to fail the
 				// scrape on errors updating the created timestamp, log debug.
-				level.Debug(sl.l).Log("msg", "Error when updating metadata in scrape loop", "series", string(met), "ct", *ctMs, "t", t, "err", err)
+				level.Debug(sl.l).Log("msg", "Error when appending CT in scrape loop", "series", string(met), "ct", *ctMs, "t", t, "err", err)
 			}
 		}
 
diff --git a/tsdb/db_test.go b/tsdb/db_test.go
index 0a604188ad..f602f5ee9d 100644
--- a/tsdb/db_test.go
+++ b/tsdb/db_test.go
@@ -6954,71 +6954,3 @@ Outer:
 
 	require.NoError(t, writerErr)
 }
-
-func TestHeadAppender_AppendCTZeroSample(t *testing.T) {
-	t.Fatalf("TODO")
-
-	// NOTE(bwplotka): We could reuse metadata test part as copied below:
-	updateMetadata := func(t *testing.T, app storage.Appender, s labels.Labels, m metadata.Metadata) {
-		_, err := app.UpdateMetadata(0, s, m)
-		require.NoError(t, err)
-	}
-
-	db := newTestDB(t)
-	ctx := context.Background()
-
-	// Add some series so we can append metadata to them.
-	app := db.Appender(ctx)
-	s1 := labels.FromStrings("a", "b")
-	s2 := labels.FromStrings("c", "d")
-	s3 := labels.FromStrings("e", "f")
-	s4 := labels.FromStrings("g", "h")
-
-	for _, s := range []labels.Labels{s1, s2, s3, s4} {
-		_, err := app.Append(0, s, 0, 0)
-		require.NoError(t, err)
-	}
-	require.NoError(t, app.Commit())
-
-	// Add a first round of metadata to the first three series.
-	// Re-take the Appender, as the previous Commit will have it closed.
-	m1 := metadata.Metadata{Type: "gauge", Unit: "unit_1", Help: "help_1"}
-	m2 := metadata.Metadata{Type: "gauge", Unit: "unit_2", Help: "help_2"}
-	m3 := metadata.Metadata{Type: "gauge", Unit: "unit_3", Help: "help_3"}
-	app = db.Appender(ctx)
-	updateMetadata(t, app, s1, m1)
-	updateMetadata(t, app, s2, m2)
-	updateMetadata(t, app, s3, m3)
-	require.NoError(t, app.Commit())
-
-	// Add a replicated metadata entry to the first series,
-	// a completely new metadata entry for the fourth series,
-	// and a changed metadata entry to the second series.
-	m4 := metadata.Metadata{Type: "counter", Unit: "unit_4", Help: "help_4"}
-	m5 := metadata.Metadata{Type: "counter", Unit: "unit_5", Help: "help_5"}
-	app = db.Appender(ctx)
-	updateMetadata(t, app, s1, m1)
-	updateMetadata(t, app, s4, m4)
-	updateMetadata(t, app, s2, m5)
-	require.NoError(t, app.Commit())
-
-	// Read the WAL to see if the disk storage format is correct.
-	recs := readTestWAL(t, path.Join(db.Dir(), "wal"))
-	var gotMetadataBlocks [][]record.RefMetadata
-	for _, rec := range recs {
-		if mr, ok := rec.([]record.RefMetadata); ok {
-			gotMetadataBlocks = append(gotMetadataBlocks, mr)
-		}
-	}
-
-	expectedMetadata := []record.RefMetadata{
-		{Ref: 1, Type: record.GetMetricType(m1.Type), Unit: m1.Unit, Help: m1.Help},
-		{Ref: 2, Type: record.GetMetricType(m2.Type), Unit: m2.Unit, Help: m2.Help},
-		{Ref: 3, Type: record.GetMetricType(m3.Type), Unit: m3.Unit, Help: m3.Help},
-		{Ref: 4, Type: record.GetMetricType(m4.Type), Unit: m4.Unit, Help: m4.Help},
-		{Ref: 2, Type: record.GetMetricType(m5.Type), Unit: m5.Unit, Help: m5.Help},
-	}
-	require.Len(t, gotMetadataBlocks, 2)
-	require.Equal(t, expectedMetadata[:3], gotMetadataBlocks[0])
-	require.Equal(t, expectedMetadata[3:], gotMetadataBlocks[1])
-}
diff --git a/tsdb/head_test.go b/tsdb/head_test.go
index 4852d1e8e7..46612aab7e 100644
--- a/tsdb/head_test.go
+++ b/tsdb/head_test.go
@@ -5642,8 +5642,8 @@ func TestPostingsCardinalityStats(t *testing.T) {
 	require.Equal(t, statsForSomeLabel1, head.PostingsCardinalityStats("n", 1))
 }
 
-func TestAppendCreatedTimestamps(t *testing.T) {
-	testCases := []struct {
+func TestHeadAppender_AppendCTZeroSample(t *testing.T) {
+	for _, tc := range []struct {
 		name       string
 		appendFunc func(*testing.T, storage.Appender)
 		assertFunc func(*testing.T, storage.Querier)
@@ -5810,9 +5810,7 @@ func TestAppendCreatedTimestamps(t *testing.T) {
 				require.Equal(t, chunkenc.ValNone, it.Next())
 			},
 		},
-	}
-
-	for _, tc := range testCases {
+	} {
 		h, _ := newTestHead(t, DefaultBlockDuration, wlog.CompressionNone, false)
 		defer func() {
 			require.NoError(t, h.Close())