diff --git a/crates/polars-expr/src/expressions/cast.rs b/crates/polars-expr/src/expressions/cast.rs
index 43301aff7189..ebfd50311918 100644
--- a/crates/polars-expr/src/expressions/cast.rs
+++ b/crates/polars-expr/src/expressions/cast.rs
@@ -13,14 +13,7 @@ pub struct CastExpr {
 
 impl CastExpr {
     fn finish(&self, input: &Series) -> PolarsResult<Series> {
-        let dtype = if input.dtype().is_list() && !self.dtype.is_nested() {
-            // Necessary for expressions that e.g. add UInt8 to List[Int64] to
-            // work.
-            &input.dtype().cast_leaf(self.dtype.clone())
-        } else {
-            &self.dtype
-        };
-        input.cast_with_options(dtype, self.options)
+        input.cast_with_options(&self.dtype, self.options)
     }
 }
 
diff --git a/crates/polars-plan/src/plans/conversion/type_coercion/binary.rs b/crates/polars-plan/src/plans/conversion/type_coercion/binary.rs
index 7ee2282b0da9..37d58e004ab1 100644
--- a/crates/polars-plan/src/plans/conversion/type_coercion/binary.rs
+++ b/crates/polars-plan/src/plans/conversion/type_coercion/binary.rs
@@ -56,11 +56,12 @@ fn process_list_arithmetic(
     expr_arena: &mut Arena<AExpr>,
 ) -> PolarsResult<Option<AExpr>> {
     match (&type_left, &type_right) {
-        (DataType::List(inner), _) => {
-            if type_right != **inner {
+        (DataType::List(_), _) => {
+            let leaf = type_left.leaf_dtype();
+            if type_right != *leaf {
                 let new_node_right = expr_arena.add(AExpr::Cast {
                     expr: node_right,
-                    dtype: *inner.clone(),
+                    dtype: type_left.cast_leaf(leaf.clone()),
                     options: CastOptions::NonStrict,
                 });
 
@@ -73,11 +74,12 @@ fn process_list_arithmetic(
                 Ok(None)
             }
         },
-        (_, DataType::List(inner)) => {
-            if type_left != **inner {
+        (_, DataType::List(_)) => {
+            let leaf = type_right.leaf_dtype();
+            if type_left != *leaf {
                 let new_node_left = expr_arena.add(AExpr::Cast {
                     expr: node_left,
-                    dtype: *inner.clone(),
+                    dtype: type_right.cast_leaf(leaf.clone()),
                     options: CastOptions::NonStrict,
                 });