diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/Case.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/Case.cs
index 64625f6a..4697f73d 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/Case.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/Case.cs
@@ -275,11 +275,13 @@ public bool Equals(Case input)
                 (
                     this.CcEmails == input.CcEmails ||
                     this.CcEmails != null &&
+                    input.CcEmails != null &&
                     this.CcEmails.SequenceEqual(input.CcEmails)
                 ) && 
                 (
                     this.Appointments == input.Appointments ||
                     this.Appointments != null &&
+                    input.Appointments != null &&
                     this.Appointments.SequenceEqual(input.Appointments)
                 ) && 
                 (
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/CaseFilters.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/CaseFilters.cs
index 9c3f64f8..69bb727b 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/CaseFilters.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/CaseFilters.cs
@@ -184,6 +184,7 @@ public bool Equals(CaseFilters input)
                 (
                     this.CaseStatuses == input.CaseStatuses ||
                     this.CaseStatuses != null &&
+                    input.CaseStatuses != null &&
                     this.CaseStatuses.SequenceEqual(input.CaseStatuses)
                 ) && 
                 (
@@ -204,11 +205,13 @@ public bool Equals(CaseFilters input)
                 (
                     this.PrimaryEmails == input.PrimaryEmails ||
                     this.PrimaryEmails != null &&
+                    input.PrimaryEmails != null &&
                     this.PrimaryEmails.SequenceEqual(input.PrimaryEmails)
                 ) && 
                 (
                     this.CcEmails == input.CcEmails ||
                     this.CcEmails != null &&
+                    input.CcEmails != null &&
                     this.CcEmails.SequenceEqual(input.CcEmails)
                 ) && 
                 (
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ChatContent.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ChatContent.cs
index c51a62ba..0c519a6d 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ChatContent.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ChatContent.cs
@@ -122,6 +122,7 @@ public bool Equals(ChatContent input)
                 (
                     this.Events == input.Events ||
                     this.Events != null &&
+                    input.Events != null &&
                     this.Events.SequenceEqual(input.Events)
                 ) && 
                 (
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ChatEvent.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ChatEvent.cs
index 4e842d9b..79a9afce 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ChatEvent.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ChatEvent.cs
@@ -207,6 +207,7 @@ public bool Equals(ChatEvent input)
                 (
                     this.Attachments == input.Attachments ||
                     this.Attachments != null &&
+                    input.Attachments != null &&
                     this.Attachments.SequenceEqual(input.Attachments)
                 );
         }
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/EmailContent.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/EmailContent.cs
index 6d317f71..e17415b2 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/EmailContent.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/EmailContent.cs
@@ -142,6 +142,7 @@ public bool Equals(EmailContent input)
                 (
                     this.Attachments == input.Attachments ||
                     this.Attachments != null &&
+                    input.Attachments != null &&
                     this.Attachments.SequenceEqual(input.Attachments)
                 );
         }
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ErrorList.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ErrorList.cs
index 2dfdba68..cdac64ba 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ErrorList.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ErrorList.cs
@@ -104,6 +104,7 @@ public bool Equals(ErrorList input)
                 (
                     this.Errors == input.Errors ||
                     this.Errors != null &&
+                    input.Errors != null &&
                     this.Errors.SequenceEqual(input.Errors)
                 );
         }
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ListCasesResult.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ListCasesResult.cs
index 64647a62..c626145a 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ListCasesResult.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ListCasesResult.cs
@@ -119,6 +119,7 @@ public bool Equals(ListCasesResult input)
                 (
                     this.Cases == input.Cases ||
                     this.Cases != null &&
+                    input.Cases != null &&
                     this.Cases.SequenceEqual(input.Cases)
                 );
         }
diff --git a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ListContactsResult.cs b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ListContactsResult.cs
index 7813bcdf..b7b423d6 100644
--- a/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ListContactsResult.cs
+++ b/Source/FikaAmazonAPI/AmazonSpApiSDK/Models/Support/ListContactsResult.cs
@@ -119,6 +119,7 @@ public bool Equals(ListContactsResult input)
                 (
                     this.Contacts == input.Contacts ||
                     this.Contacts != null &&
+                    input.Contacts != null &&
                     this.Contacts.SequenceEqual(input.Contacts)
                 );
         }
diff --git a/Source/Tests/SupportTests.cs b/Source/Tests/SupportTests.cs
index e6066383..62359882 100644
--- a/Source/Tests/SupportTests.cs
+++ b/Source/Tests/SupportTests.cs
@@ -58,6 +58,18 @@ public void ListContactsResult_DeserialisesChatEvents()
             Assert.That(contact.ChatContent.Events[0].Participant.Role, Is.EqualTo(Participant.RoleEnum.AMAZON));
         }
 
+        [Test]
+        public void Equals_ReturnsFalseWhenOnlyOneSideHasAList()
+        {
+            var timestamp = new DateTime(2024, 1, 12, 11, 0, 0, DateTimeKind.Utc);
+            var withAttachments = new ChatEvent(timestamp: timestamp, type: ChatEvent.TypeEnum.ATTACHMENT,
+                attachments: new List<Attachment> { new Attachment(name: "file.txt") });
+            var withoutAttachments = new ChatEvent(timestamp: timestamp, type: ChatEvent.TypeEnum.ATTACHMENT);
+
+            Assert.That(withAttachments.Equals(withoutAttachments), Is.False);
+            Assert.That(withoutAttachments.Equals(withAttachments), Is.False);
+        }
+
         [Test]
         public void ParameterListCases_SerialisesToAmazonRequestBody()
         {