diff --git a/CryptoExchange.Net.UnitTests/SystemTextJsonConverterTests.cs b/CryptoExchange.Net.UnitTests/SystemTextJsonConverterTests.cs
index 339be78..970c39e 100644
--- a/CryptoExchange.Net.UnitTests/SystemTextJsonConverterTests.cs
+++ b/CryptoExchange.Net.UnitTests/SystemTextJsonConverterTests.cs
@@ -1,11 +1,15 @@
 using CryptoExchange.Net.Attributes;
+using CryptoExchange.Net.Converters;
 using CryptoExchange.Net.Converters.SystemTextJson;
-using System.Text.Json;
+using CryptoExchange.Net.Objects;
+using CryptoExchange.Net.SharedApis;
+using CryptoExchange.Net.Testing;
+using Newtonsoft.Json.Linq;
 using NUnit.Framework;
 using System;
+using System.Diagnostics;
+using System.Text.Json;
 using System.Text.Json.Serialization;
-using CryptoExchange.Net.Converters;
-using CryptoExchange.Net.SharedApis;
 
 namespace CryptoExchange.Net.UnitTests
 {
@@ -185,6 +189,30 @@ namespace CryptoExchange.Net.UnitTests
             Assert.That(result == expected);
         }
 
+        [Test]
+        public void TestEnumConverterParseNullOnNonNullableOnlyLogsOnce()
+        {
+            LibraryHelpers.StaticLogger = new TraceLogger();
+            var listener = new EnumValueTraceListener();
+            Trace.Listeners.Add(listener);
+            try
+            {
+                Assert.Throws<Exception>(() =>
+                {
+                    var result = JsonSerializer.Deserialize<NotNullableSTJEnumObject>("{\"Value\": null}", SerializerOptions.WithConverters(new SerializationContext()));
+                });
+
+                Assert.DoesNotThrow(() =>
+                {
+                    var result2 = JsonSerializer.Deserialize<NotNullableSTJEnumObject>("{\"Value\": null}", SerializerOptions.WithConverters(new SerializationContext()));
+                });
+            }
+            finally
+            {
+                Trace.Listeners.Remove(listener);
+            }
+        }
+
         [TestCase("1", true)]
         [TestCase("true", true)]
         [TestCase("yes", true)]
diff --git a/CryptoExchange.Net/Converters/SystemTextJson/EnumConverter.cs b/CryptoExchange.Net/Converters/SystemTextJson/EnumConverter.cs
index 2c64f34..fe7c444 100644
--- a/CryptoExchange.Net/Converters/SystemTextJson/EnumConverter.cs
+++ b/CryptoExchange.Net/Converters/SystemTextJson/EnumConverter.cs
@@ -120,13 +120,14 @@ namespace CryptoExchange.Net.Converters.SystemTextJson
         /// <inheritdoc />
         public override T Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
         {
-            var t = ReadNullable(ref reader, typeToConvert, options, out var isEmptyString);
+            var t = ReadNullable(ref reader, typeToConvert, options, out var isEmptyStringOrNull);
             if (t != null)
                 return t.Value;
             
-            if (isEmptyString && !_unknownValuesWarned.Contains(null))
+            if (isEmptyStringOrNull && !_unknownValuesWarned.Contains(null))
             {
                 // We received an empty string and have no mapping for it, and the property isn't nullable
+                _unknownValuesWarned.Add(null!);
                 LibraryHelpers.StaticLogger?.LogWarning($"Received null or empty enum value, but property type is not a nullable enum. EnumType: {typeof(T).FullName}. If you think {typeof(T).FullName} should be nullable please open an issue on the Github repo");
             }
 
@@ -149,9 +150,9 @@ namespace CryptoExchange.Net.Converters.SystemTextJson
             return (T)_undefinedEnumValue;
         }
 
-        private T? ReadNullable(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options, out bool isEmptyString)
+        private T? ReadNullable(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options, out bool isEmptyStringOrNull)
         {
-            isEmptyString = false;
+            isEmptyStringOrNull = false;
             var enumType = typeof(T);
             if (_mappingToEnum == null)
                 CreateMapping();
@@ -167,13 +168,16 @@ namespace CryptoExchange.Net.Converters.SystemTextJson
             };
 
             if (stringValue is null)
+            {
+                isEmptyStringOrNull = true;
                 return null;
+            }
 
             if (!GetValue(enumType, stringValue, out var result))
             {
                 if (string.IsNullOrWhiteSpace(stringValue))
                 {
-                    isEmptyString = true;
+                    isEmptyStringOrNull = true;
                 }
                 else
                 {
diff --git a/CryptoExchange.Net/Testing/EnumValueTraceListener.cs b/CryptoExchange.Net/Testing/EnumValueTraceListener.cs
index 3b13193..9dc30e8 100644
--- a/CryptoExchange.Net/Testing/EnumValueTraceListener.cs
+++ b/CryptoExchange.Net/Testing/EnumValueTraceListener.cs
@@ -13,7 +13,7 @@ namespace CryptoExchange.Net.Testing
             if (message.Contains("Cannot map"))
                 throw new Exception("Enum value error: " + message);
 
-            if (message.Contains("Received null enum value"))
+            if (message.Contains("Received null or empty enum value"))
                 throw new Exception("Enum null error: " + message);
         }
 
@@ -25,7 +25,7 @@ namespace CryptoExchange.Net.Testing
             if (message.Contains("Cannot map"))
                 throw new Exception("Enum value error: " + message);
 
-            if (message.Contains("Received null enum value"))
+            if (message.Contains("Received null or empty enum value"))
                 throw new Exception("Enum null error: " + message);
         }
     }