diff --git a/masque/builder/pather.py b/masque/builder/pather.py
index fb13260..76e45b7 100644
--- a/masque/builder/pather.py
+++ b/masque/builder/pather.py
@@ -535,7 +535,7 @@ class Pather(PortList):
             if isinstance(portspec, str):
                 portspec = [portspec]
             pos_keys = {'p', 'x', 'y', 'pos', 'position'}
-            pb = {k: bounds[k] for k in bounds if k in pos_keys}
+            pb = {k: bounds[k] for k in bounds if k in pos_keys and bounds[k] is not None}
             if pb:
                 if len(portspec) > 1:
                     raise BuildError('Position bounds only allowed with a single port')
diff --git a/masque/test/test_pather_api.py b/masque/test/test_pather_api.py
index 799896b..54a06be 100644
--- a/masque/test/test_pather_api.py
+++ b/masque/test/test_pather_api.py
@@ -279,6 +279,16 @@ def test_pather_trace_into() -> None:
     assert p.pattern.ports['G'].rotation is not None
     assert numpy.isclose(p.pattern.ports['G'].rotation, pi)
 
+    # 5. Vertical straight connector
+    p.pattern.ports['I'] = Port((0, 0), rotation=pi / 2)
+    p.pattern.ports['J'] = Port((0, -10000), rotation=3 * pi / 2)
+    p.at('I').trace_into('J', plug_destination=False)
+    assert 'J' in p.pattern.ports
+    assert 'I' in p.pattern.ports
+    assert numpy.allclose(p.pattern.ports['I'].offset, (0, -10000))
+    assert p.pattern.ports['I'].rotation is not None
+    assert numpy.isclose(p.pattern.ports['I'].rotation, pi / 2)
+
 
 def test_pather_jog_failed_fallback_is_atomic() -> None:
     lib = Library()