diff --git a/debye_bec/scans/nidaq_continuous_scan.py b/debye_bec/scans/nidaq_continuous_scan.py
index 6a5da9d..d1afd99 100644
--- a/debye_bec/scans/nidaq_continuous_scan.py
+++ b/debye_bec/scans/nidaq_continuous_scan.py
@@ -71,7 +71,11 @@ class NidaqContinuousScan(ScanBase):
         self.motors = [self.daq]
 
         self.update_scan_info(scan_duration=scan_duration, compression=compression)
-        self.actions.set_device_readout_priority([self.daq], priority="async")
+        # NOTE: the daq is deliberately NOT promoted to async readout priority:
+        # the file writer would then ALSO consume the backend's legacy
+        # device_async_readback stream, whose signal names are now identical to
+        # the bridged ones, double-writing every dataset. The unified-bridge
+        # emission on device_async_signal is stored for every scan regardless.
 
     @scan_hook
     def prepare_scan(self):
diff --git a/debye_bec/scans/xas_simple_scan.py b/debye_bec/scans/xas_simple_scan.py
index d6a313f..dad2973 100644
--- a/debye_bec/scans/xas_simple_scan.py
+++ b/debye_bec/scans/xas_simple_scan.py
@@ -80,7 +80,11 @@ class XasSimpleScan(ScanBase):
             scan_duration=scan_duration,
             monitored_readout_cycle=monitored_readout_cycle,
         )
-        self.actions.set_device_readout_priority([self.daq], priority="async")
+        # NOTE: the daq is deliberately NOT promoted to async readout priority:
+        # the file writer would then ALSO consume the backend's legacy
+        # device_async_readback stream, whose signal names are now identical to
+        # the bridged ones, double-writing every dataset. The unified-bridge
+        # emission on device_async_signal is stored for every scan regardless.
 
     @scan_hook
     def prepare_scan(self):
diff --git a/tests/tests_scans/test_mono_bragg_scans_v4.py b/tests/tests_scans/test_mono_bragg_scans_v4.py
index e33fe92..fab5f6f 100644
--- a/tests/tests_scans/test_mono_bragg_scans_v4.py
+++ b/tests/tests_scans/test_mono_bragg_scans_v4.py
@@ -52,7 +52,10 @@ def test_xas_simple_scan_v4_prepare_scan_updates_metadata(v4_scan_assembler):
     np.testing.assert_array_equal(scan.scan_info.positions, np.array([8000.0, 9000.0]))
     assert scan.scan_info.additional_scan_parameters["scan_time"] == 1.0
     assert scan.scan_info.additional_scan_parameters["scan_duration"] == 10.0
-    assert scan.scan_info.readout_priority_modification["async"] == ["nidaq"]
+    # the daq is no longer promoted to async: with unified channel-first
+    # names the writer must consume ONLY the bridged device_async_signal
+    # streams, never the backend's legacy per-device stream in parallel
+    assert scan.scan_info.readout_priority_modification["async"] == []
     scan.actions.add_scan_report_instruction_device_progress.assert_called_once_with(scan.motor)
     scan.actions.read_baseline_devices.assert_called_once_with(wait=False)
     assert scan._baseline_readout_status is baseline_status
diff --git a/tests/tests_scans/test_nidaq_continous_scan.py b/tests/tests_scans/test_nidaq_continous_scan.py
index f2c10ec..6679939 100644
--- a/tests/tests_scans/test_nidaq_continous_scan.py
+++ b/tests/tests_scans/test_nidaq_continous_scan.py
@@ -41,7 +41,10 @@ def test_nidaq_continuous_scan_v4_prepare_scan_updates_metadata(v4_scan_assemble
 
     assert scan.scan_info.additional_scan_parameters["scan_duration"] == 10.0
     assert scan.scan_info.additional_scan_parameters["compression"] is False
-    assert scan.scan_info.readout_priority_modification["async"] == ["nidaq"]
+    # the daq is no longer promoted to async: with unified channel-first
+    # names the writer must consume ONLY the bridged device_async_signal
+    # streams, never the backend's legacy per-device stream in parallel
+    assert scan.scan_info.readout_priority_modification["async"] == []
     scan.actions.add_scan_report_instruction_device_progress.assert_called_once_with(scan.daq)
     scan.actions.read_baseline_devices.assert_called_once_with(wait=False)
     assert scan._baseline_readout_status is baseline_status