diff --git a/src/db/unit_tests/dbHierNetworkProcessorTests.cc b/src/db/unit_tests/dbHierNetworkProcessorTests.cc
index 8ef049e6f..06798f741 100644
--- a/src/db/unit_tests/dbHierNetworkProcessorTests.cc
+++ b/src/db/unit_tests/dbHierNetworkProcessorTests.cc
@@ -877,7 +877,7 @@ static void copy_cluster_shapes (const std::string *&attrs, db::Shapes &out, db:
 static void run_hc_test (tl::TestBase *_this, const std::string &file, const std::string &au_file)
 {
   db::Layout ly;
-  unsigned int l1 = 0, l2 = 0, l3 = 0, l4 = 0;
+  unsigned int l1 = 0, l2 = 0, l3 = 0, l4 = 0, l5 = 0, l6 = 0;
 
   {
     db::LayerProperties p;
@@ -903,6 +903,16 @@ static void run_hc_test (tl::TestBase *_this, const std::string &file, const std
     lmap.map (db::LDPair (p.layer, p.datatype), l4 = ly.insert_layer ());
     ly.set_properties (l4, p);
 
+    p.layer = 5;
+    p.datatype = 0;
+    lmap.map (db::LDPair (p.layer, p.datatype), l5 = ly.insert_layer ());
+    ly.set_properties (l5, p);
+
+    p.layer = 6;
+    p.datatype = 0;
+    lmap.map (db::LDPair (p.layer, p.datatype), l6 = ly.insert_layer ());
+    ly.set_properties (l6, p);
+
     db::LoadLayoutOptions options;
     options.get_options<db::CommonReaderOptions> ().layer_map = lmap;
     options.get_options<db::CommonReaderOptions> ().create_other_layers = false;
@@ -920,6 +930,8 @@ static void run_hc_test (tl::TestBase *_this, const std::string &file, const std
   normalize_layer (ly, strings, l2);
   normalize_layer (ly, strings, l3);
   normalize_layer (ly, strings, l4);
+  normalize_layer (ly, strings, l5);
+  normalize_layer (ly, strings, l6);
 
   //  connect 1 to 1, 1 to 2 and 1 to 3, but *not* 2 to 3
   db::Connectivity conn;
@@ -929,8 +941,13 @@ static void run_hc_test (tl::TestBase *_this, const std::string &file, const std
   conn.connect (l1, l2);
   conn.connect (l1, l3);
   conn.connect (l1, l4);
+  conn.connect (l1, l5);
+  conn.connect (l1, l6);
 
   conn.connect_global (l4, "BULK");
+  conn.connect_global (l5, "BULK2");
+  conn.connect_global (l6, "BULK");
+  conn.connect_global (l6, "BULK2");
 
   db::hier_clusters<db::PolygonRef> hc;
   hc.build (ly, ly.cell (*ly.begin_top_down ()), db::ShapeIterator::Polygons, conn);
@@ -993,7 +1010,7 @@ static void run_hc_test (tl::TestBase *_this, const std::string &file, const std
 static void run_hc_test_with_backannotation (tl::TestBase *_this, const std::string &file, const std::string &au_file)
 {
   db::Layout ly;
-  unsigned int l1 = 0, l2 = 0, l3 = 0, l4 = 0;
+  unsigned int l1 = 0, l2 = 0, l3 = 0, l4 = 0, l5 = 0, l6 = 0;
 
   {
     db::LayerProperties p;
@@ -1019,6 +1036,16 @@ static void run_hc_test_with_backannotation (tl::TestBase *_this, const std::str
     lmap.map (db::LDPair (p.layer, p.datatype), l4 = ly.insert_layer ());
     ly.set_properties (l4, p);
 
+    p.layer = 5;
+    p.datatype = 0;
+    lmap.map (db::LDPair (p.layer, p.datatype), l5 = ly.insert_layer ());
+    ly.set_properties (l5, p);
+
+    p.layer = 6;
+    p.datatype = 0;
+    lmap.map (db::LDPair (p.layer, p.datatype), l6 = ly.insert_layer ());
+    ly.set_properties (l6, p);
+
     db::LoadLayoutOptions options;
     options.get_options<db::CommonReaderOptions> ().layer_map = lmap;
     options.get_options<db::CommonReaderOptions> ().create_other_layers = false;
@@ -1036,6 +1063,8 @@ static void run_hc_test_with_backannotation (tl::TestBase *_this, const std::str
   normalize_layer (ly, strings, l2);
   normalize_layer (ly, strings, l3);
   normalize_layer (ly, strings, l4);
+  normalize_layer (ly, strings, l5);
+  normalize_layer (ly, strings, l6);
 
   //  connect 1 to 1, 1 to 2 and 1 to 3, but *not* 2 to 3
   db::Connectivity conn;
@@ -1045,8 +1074,13 @@ static void run_hc_test_with_backannotation (tl::TestBase *_this, const std::str
   conn.connect (l1, l2);
   conn.connect (l1, l3);
   conn.connect (l1, l4);
+  conn.connect (l1, l5);
+  conn.connect (l1, l6);
 
   conn.connect_global (l4, "BULK");
+  conn.connect_global (l5, "BULK2");
+  conn.connect_global (l6, "BULK");
+  conn.connect_global (l6, "BULK2");
 
   db::hier_clusters<db::PolygonRef> hc;
   hc.build (ly, ly.cell (*ly.begin_top_down ()), db::ShapeIterator::Polygons, conn);
@@ -1056,6 +1090,8 @@ static void run_hc_test_with_backannotation (tl::TestBase *_this, const std::str
   lm[l2] = ly.insert_layer (db::LayerProperties (102, 0));
   lm[l3] = ly.insert_layer (db::LayerProperties (103, 0));
   lm[l4] = ly.insert_layer (db::LayerProperties (104, 0));
+  lm[l5] = ly.insert_layer (db::LayerProperties (105, 0));
+  lm[l6] = ly.insert_layer (db::LayerProperties (106, 0));
   hc.return_to_hierarchy (ly, lm);
 
   CHECKPOINT();
@@ -1158,3 +1194,9 @@ TEST(116_HierClusters)
   run_hc_test_with_backannotation (_this, "hc_test_l16.gds", "hc_test_au16b.gds");
 }
 
+TEST(117_HierClusters)
+{
+  run_hc_test (_this, "hc_test_l17.gds", "hc_test_au17.gds");
+  run_hc_test_with_backannotation (_this, "hc_test_l17.gds", "hc_test_au17b.gds");
+}
+
diff --git a/testdata/algo/hc_test_au17.gds b/testdata/algo/hc_test_au17.gds
new file mode 100644
index 000000000..d4ae2eb93
Binary files /dev/null and b/testdata/algo/hc_test_au17.gds differ
diff --git a/testdata/algo/hc_test_au17b.gds b/testdata/algo/hc_test_au17b.gds
new file mode 100644
index 000000000..441679c28
Binary files /dev/null and b/testdata/algo/hc_test_au17b.gds differ
diff --git a/testdata/algo/hc_test_l17.gds b/testdata/algo/hc_test_l17.gds
new file mode 100644
index 000000000..4ddd3a2a7
Binary files /dev/null and b/testdata/algo/hc_test_l17.gds differ