diff --git a/nnpdf_data/nnpdf_data/__init__.py b/nnpdf_data/nnpdf_data/__init__.py
index 341d863d5b..a6eeec892d 100644
--- a/nnpdf_data/nnpdf_data/__init__.py
+++ b/nnpdf_data/nnpdf_data/__init__.py
@@ -64,7 +64,7 @@ def new_to_legacy_map(dataset_name, variant_used):
             matches.append(old_name)
             # if it's a nuclear DIS data promote legacy to be legacy_dw
             if "_DW_" in old_name and variant_used == "legacy":
-                variant_used = "legacy_dw"
+                variant = "legacy_dw"
 
             if variant_used == variant:
                 exact_matches.append(old_name)
diff --git a/validphys2/src/validphys/tests/test_commondataparser.py b/validphys2/src/validphys/tests/test_commondataparser.py
index 13205e9f0f..a1ce493652 100644
--- a/validphys2/src/validphys/tests/test_commondataparser.py
+++ b/validphys2/src/validphys/tests/test_commondataparser.py
@@ -128,3 +128,5 @@ def test_variant_nnpdf_metadata():
         assert pcd2.experiment != pcd1.experiment
         # but the real experiment is the same
         assert cd1.metadata.experiment == cd2.metadata.experiment
+        # And check that the legacy names are _not_ the same
+        assert cd1.legacy_names != cd2.legacy_names