diff --git a/myhdl/test/bugs/test_issue_169.py b/myhdl/test/bugs/test_issue_169.py
new file mode 100644
index 00000000..905decd7
--- /dev/null
+++ b/myhdl/test/bugs/test_issue_169.py
@@ -0,0 +1,56 @@
+from myhdl import Signal, block, delay, instance
+
+import pytest
+
+
+class Test1:
+    def __init__(self):
+        self.clock = Signal(bool(0))
+
+    @block
+    def test(self):
+    
+        @instance
+        def func():
+            while True:
+                yield delay(10)
+                self.clock.next = not self.clock
+
+        return func
+
+
+class Test2:
+    def __init__(self):
+        self.clock = Signal(bool(1))
+
+    @block
+    def test(self):
+    
+        @instance
+        def func():
+            while True:
+                yield delay(10)
+                self.clock.next = not self.clock
+
+        return func
+
+
+@block
+def test_bench():
+    inst1 = Test1()
+    inst2 = Test2()
+    
+    # Two instances are created
+    ins1 = inst1.test()
+    ins2 = inst2.test()
+
+    return ins1, ins2
+
+@pytest.mark.xfail
+def test_issue_169():
+    test_inst = testbench()
+    assert test_inst.verify_convert() == 0
+    
+if __name__ == '__main__':
+    test_issue_169()
+