diff --git a/masque/builder/tools.py b/masque/builder/tools.py
index 923e4a3..af49d44 100644
--- a/masque/builder/tools.py
+++ b/masque/builder/tools.py
@@ -1014,7 +1014,7 @@ class AutoTool(Tool, metaclass=ABCMeta):
             return numpy.zeros(2)
         orot = out_transition.our_port.rotation
         assert orot is not None
-        otrans_dxy = rotation_matrix_2d(pi - orot - bend_angle) @ (out_transition.their_port.offset - out_transition.our_port.offset)
+        otrans_dxy = rotation_matrix_2d(bend_angle - orot - pi) @ (out_transition.their_port.offset - out_transition.our_port.offset)
         return otrans_dxy
 
     def planL(
diff --git a/masque/test/test_autotool_refactor.py b/masque/test/test_autotool_refactor.py
index 3109447..2f560cb 100644
--- a/masque/test/test_autotool_refactor.py
+++ b/masque/test/test_autotool_refactor.py
@@ -132,6 +132,49 @@ def test_autotool_planL_selection(multi_bend_tool) -> None:
     assert data.straight_length == 13
     assert_allclose(p.offset, [15, 2])
 
+
+@pytest.mark.parametrize("ccw", [False, True])
+def test_autotool_traceL_matches_plan_with_post_bend_transition(ccw: bool) -> None:
+    lib = Library()
+
+    bend_pat = Pattern()
+    bend_pat.ports["A"] = Port((0, 0), 0, ptype="core")
+    bend_pat.ports["B"] = Port((2, -2), pi / 2, ptype="core")
+    lib["core_bend"] = bend_pat
+
+    trans_pat = Pattern()
+    trans_pat.ports["CORE"] = Port((0, 0), 0, ptype="core")
+    trans_pat.ports["EXT"] = Port((3, 1), pi, ptype="ext")
+    lib["out_trans"] = trans_pat
+
+    tool = AutoTool(
+        straights=[
+            AutoTool.Straight(
+                ptype="core",
+                fn=lambda length: make_straight(length, ptype="core"),
+                in_port_name="A",
+                out_port_name="B",
+                length_range=(0, 1e8),
+                ),
+            ],
+        bends=[
+            AutoTool.Bend(lib.abstract("core_bend"), "A", "B", clockwise=True, mirror=True),
+            ],
+        sbends=[],
+        transitions={
+            ("ext", "core"): AutoTool.Transition(lib.abstract("out_trans"), "EXT", "CORE"),
+            },
+        default_out_ptype="core",
+        )
+
+    plan_port, data = tool.planL(ccw, 10, out_ptype="ext")
+
+    assert data.out_transition is not None
+
+    tree = tool.traceL(ccw, 10, out_ptype="ext")
+    assert_trace_matches_plan(plan_port, tree)
+
+
 def test_autotool_planU_consistency(multi_bend_tool) -> None:
     tool, lib = multi_bend_tool