diff --git a/tests/GameCult.Caching.Tests/UnionArmGuardTests.cs b/tests/GameCult.Caching.Tests/UnionArmGuardTests.cs
index eed82076..7c98927b 100644
--- a/tests/GameCult.Caching.Tests/UnionArmGuardTests.cs
+++ b/tests/GameCult.Caching.Tests/UnionArmGuardTests.cs
@@ -357,47 +357,6 @@ namespace GameCult.Caching.Tests
             Assert.That(Convert.ToHexString(plainBytes), Is.EqualTo(Convert.ToHexString(MessagePackSerializer.Serialize(plain, CultDocumentMessagePackSerialization.Options))));
         }
 
-        // StandardResolverAllowPrivate cannot always build a formatter (a private [Key] delegate member has none). That is not an
-        // escape from the claim check: a resolver formatting such a type is refused like any other.
-        [Test]
-        public void AFormatterThatStandardResolverAllowPrivateCannotBuildStillClaims()
-        {
-            var registry = CultDocumentRegistry.ForTypes(new[] { typeof(ApHookDoc) });
-            var doc = new ApHookDoc { Id = "r1", Items = { new ApHookArm { Id = "00000000000c" } } };
-
-            var thrown = Assert.Throws<InvalidOperationException>(() => CultDocumentMessagePackSerialization.SerializeUntyped(doc, typeof(ApHookDoc), registry))!;
-
-            Assert.That(thrown.Message, Does.Contain(nameof(ListClaimResolver)).And.Contain(nameof(ApHookArm)));
-        }
-
-        [MessagePackObject]
-        public sealed class ApHookArm
-        {
-            [Key(0)] [CultElementId] public string Id = string.Empty;
-#pragma warning disable CS0169, CS0649
-            [Key(1)] private Action? hook;
-#pragma warning restore CS0169, CS0649
-        }
-
-        [CultDocument("tests.ap_hook_doc", "tests.ap_hook_doc.v1")]
-        [MessagePackObject]
-        public sealed class ApHookDoc
-        {
-            [Key(0)] [CultName] public string Id = string.Empty;
-            [Key(1)] public List<ApHookArm> Items = new();
-        }
-
-        private sealed class ApHookFormatter : IMessagePackFormatter<ApHookArm>
-        {
-            public void Serialize(ref MessagePackWriter writer, ApHookArm value, MessagePackSerializerOptions options) => writer.WriteNil();
-
-            public ApHookArm Deserialize(ref MessagePackReader reader, MessagePackSerializerOptions options)
-            {
-                reader.Skip();
-                return new ApHookArm();
-            }
-        }
-
         [MessagePackObject]
         public sealed class ApArm
         {
@@ -498,7 +457,6 @@ namespace GameCult.Caching.Tests
                 if (typeof(T) == typeof(List<LcValue>)) return (IMessagePackFormatter<T>)(object)new ValuesFormatter();
                 if (typeof(T) == typeof(List<Pair>)) return (IMessagePackFormatter<T>)(object)new PointsFormatter();
                 if (typeof(T) == typeof(FbArm)) return global::MessagePack.Resolvers.StandardResolver.Instance.GetFormatter<T>();
-                if (typeof(T) == typeof(ApHookArm)) return (IMessagePackFormatter<T>)(object)new ApHookFormatter();
                 if (typeof(T) == typeof(ApArm) || typeof(T) == typeof(ApDoc) || typeof(T) == typeof(List<ApArm>) ||
                     typeof(T) == typeof(ApPlainArm) || typeof(T) == typeof(ApPlainDoc) || typeof(T) == typeof(List<ApPlainArm>))
                     return global::MessagePack.Resolvers.StandardResolverAllowPrivate.Instance.GetFormatter<T>();