diff --git a/narwhals/_arrow/expr.py b/narwhals/_arrow/expr.py
index d2d51dac7..b8aba0aef 100644
--- a/narwhals/_arrow/expr.py
+++ b/narwhals/_arrow/expr.py
@@ -395,17 +395,16 @@ def func(df: ArrowDataFrame) -> list[ArrowSeries]:
             output_names = [input_series.name for input_series in input_series_list]
             result = [function(series) for series in input_series_list]
 
-            if (
-                is_numpy_array(result[0])
-                or (np := get_numpy()) is not None
-                and np.isscalar(result[0])
-            ):
+            if is_numpy_array(result[0]):
                 result = [
                     df.__narwhals_namespace__()
                     ._create_compliant_series(array)
                     .alias(output_name)
-                    if is_numpy_array(array)
-                    else df.__narwhals_namespace__()
+                    for array, output_name in zip(result, output_names)
+                ]
+            elif (np := get_numpy()) is not None and np.isscalar(result[0]):
+                result = [
+                    df.__narwhals_namespace__()
                     ._create_compliant_series([array])
                     .alias(output_name)
                     for array, output_name in zip(result, output_names)
diff --git a/narwhals/_pandas_like/expr.py b/narwhals/_pandas_like/expr.py
index 58ba633dd..6b2487dcb 100644
--- a/narwhals/_pandas_like/expr.py
+++ b/narwhals/_pandas_like/expr.py
@@ -410,10 +410,8 @@ def func(df: PandasLikeDataFrame) -> list[PandasLikeSeries]:
             input_series_list = self._call(df)
             output_names = [input_series.name for input_series in input_series_list]
             result = [function(series) for series in input_series_list]
-            if (
-                is_numpy_array(result[0])
-                or (np := get_numpy()) is not None
-                and np.isscalar(result[0])
+            if is_numpy_array(result[0]) or (
+                (np := get_numpy()) is not None and np.isscalar(result[0])
             ):
                 result = [
                     df.__narwhals_namespace__()