diff --git a/crates/nu-command/tests/commands/assignment/append_assign.rs b/crates/nu-command/tests/commands/assignment/append_assign.rs
index 74aa88da1..fea472920 100644
--- a/crates/nu-command/tests/commands/assignment/append_assign.rs
+++ b/crates/nu-command/tests/commands/assignment/append_assign.rs
@@ -99,10 +99,9 @@ fn append_assign_type_mismatch() {
         r#"
             mut a = [1 2];
             $a ++= [a];
+            $a | to json -r;
         "#
     ));
 
-    assert!(actual
-        .err
-        .contains("expected list<int>, found list<string>"));
+    assert_eq!(actual.out, r#"[1,2,"a"]"#);
 }
diff --git a/crates/nu-parser/src/type_check.rs b/crates/nu-parser/src/type_check.rs
index 2d5ef6fba..13c0f3c93 100644
--- a/crates/nu-parser/src/type_check.rs
+++ b/crates/nu-parser/src/type_check.rs
@@ -568,6 +568,7 @@ pub fn math_result_type(
                 (x, y) if x == y => (Type::Nothing, None),
                 (Type::Any, _) => (Type::Nothing, None),
                 (_, Type::Any) => (Type::Nothing, None),
+                (Type::List(_), Type::List(_)) => (Type::Nothing, None),
                 (x, y) => (
                     Type::Nothing,
                     Some(ParseError::Mismatch(x.to_string(), y.to_string(), rhs.span)),