diff --git a/tests/validation/multigrid/test_refinement_jets.py b/tests/validation/multigrid/test_refinement_jets.py
index 558c916..485332b 100644
--- a/tests/validation/multigrid/test_refinement_jets.py
+++ b/tests/validation/multigrid/test_refinement_jets.py
@@ -18,7 +18,7 @@ import pycuda.driver as cuda
 
 from CelerisLab.cuda import compiler_v2 as compiler
 from CelerisLab.lbm.descriptors import SOLID
-from CelerisLab.lbm.refinement import ACTIVE, FixedPatch2D
+from CelerisLab.lbm.refinement import ACTIVE, FixedPatch2D, prepare_fine_boundary
 from CelerisLab.lbm.refinement_stepper import FixedPatchStepper
 from test_refinement_blocked_fine import (BOUNDS, FINE_BLOCKS, NX, NY, STEPS, actuation,
                                           circle, config, fine_circle, raw, state)
@@ -58,6 +58,34 @@ class JetStepperCPU(unittest.TestCase):
         self.assertGreater(len(np.unique(backend._fine_tables["block"][jet_id == 0])), 1)
         backend.close()
 
+    def test_fine_ownership_uses_remapped_physical_owner(self):
+        # Caller ids (99, 7) are remapped to fine owners (0, 1); block ids never count.
+        import math
+        from CelerisLab.body.geometry.circle import CircleGeometry
+        from CelerisLab.body.jets import Jet, Parallel, Radial, Sector, Tube
+        from CelerisLab.body.objects import SimObject
+        C = (16.0, 12.0)
+        source = SimObject(99, geometry=CircleGeometry(*C, 2.15), center=C, radius=2.15)
+        whole = Jet(Sector(C, .1, math.pi, 3.), Radial(C, inward=False), amplitude=0.)
+        backend, _ = mocked([source], [whole], FINE_BLOCKS[1])
+        _, jet_id = backend._jet_cache
+        owners = backend.fine_boundary.curved_host[3][jet_id == 0]
+        self.assertEqual(np.unique(owners).tolist(), [0])
+        self.assertGreater(len(np.unique(backend._fine_tables["block"][jet_id == 0])), 1)
+        self.assertEqual(source.obj_id, 99)
+        backend.close()
+        cfg = config("periodic")
+        patch_ = FixedPatch2D.from_config(cfg, BOUNDS)
+        A, B = (12.5, 12.0), (19.5, 12.0)
+        pair = [SimObject(i, geometry=CircleGeometry(*c, 1.5), center=c, radius=1.5)
+                for i, c in ((99, A), (7, B))]
+        for amplitude in (0., .002):
+            with self.assertRaisesRegex(ValueError, "one jet may drive only one body"):
+                prepare_fine_boundary(cfg, patch_, pair,
+                                      jets=[Jet(Tube((9., 12.), 0., 14., .5), Parallel(0.),
+                                                amplitude=amplitude)])
+        self.assertEqual([o.obj_id for o in pair], [99, 7])
+
     def test_blocked_jet_velocity_matches_legacy_rows(self):
         legacy, _ = mocked([circle(actuation(SPEED))], (), FINE_BLOCKS[1])
         driven, _ = mocked([circle()], [jet()], FINE_BLOCKS[1])