diff --git a/tests/validation/multigrid/test_raw_exchange_gpu.py b/tests/validation/multigrid/test_raw_exchange_gpu.py
index 25ec7ad..724fbaa 100644
--- a/tests/validation/multigrid/test_raw_exchange_gpu.py
+++ b/tests/validation/multigrid/test_raw_exchange_gpu.py
@@ -239,16 +239,17 @@ class RawExchangeGPU(unittest.TestCase):
                 np.testing.assert_array_equal([v.dir for v in links], b.tables['dir'])
                 np.testing.assert_allclose([v.q for v in links], b.tables['q'], atol=2e-7, rtol=0)
                 # Same fine-grid force arms after translation to the same center: the
-                # single level's static BFL gets the AMR Jet column and raw ledger inputs.
+                # single level's static BFL gets the AMR Jet column and force arms; the raw
+                # output pointer is substituted at launch (no stepper-side accumulation).
                 root = uniform._level_boundaries[0]
                 velocity = uniform._upload(b.tables['surface_velocity'])
                 root.device.update(surface_velocity=velocity, rx=uniform._upload(b.tables['rx']),
                                    ry=uniform._upload(b.tables['ry']))
-                root.last_raw = raw = uniform._allocate(count*16)
+                raw = uniform._allocate(count*16)
                 original = root.kernel
                 samples = []
                 def measured_boundary(*args, **kw):
-                    original(*args, **kw)
+                    original(*args[:10], raw, **kw)  # BlockCurvedBoundary raw-exchange output
                     uniform._stream.synchronize()
                     samples.append(download(raw, (count, 4)))
                 root.kernel = measured_boundary