diff --git a/Sources/ManagedModels/PersistentModel/PersistentModel+KVC.swift b/Sources/ManagedModels/PersistentModel/PersistentModel+KVC.swift
index 4bb2bed..c83eb0d 100644
--- a/Sources/ManagedModels/PersistentModel/PersistentModel+KVC.swift
+++ b/Sources/ManagedModels/PersistentModel/PersistentModel+KVC.swift
@@ -31,7 +31,15 @@ public extension PersistentModel {
     where T: Codable & CoreDataPrimitiveValue & AnyOptional
   {
     willChangeValue(forKey: key); defer { didChangeValue(forKey: key) }
-    setPrimitiveValue(value, forKey: key)
+    
+    // While `nil` is properly bridged to `NSNull`, this is still necessary
+    // because `T` is the Optional structure, NOT the value type. I think :-)
+    if value.isSome {
+      setPrimitiveValue(value.value, forKey: key)
+    }
+    else {
+      setPrimitiveValue(nil, forKey: key)
+    }
   }
   @inlinable
   func getValue<T>(forKey key: String) -> T
diff --git a/Tests/ManagedModelTests/CoreDataAssumptionsTests.swift b/Tests/ManagedModelTests/CoreDataAssumptionsTests.swift
index 3da87a0..204036d 100644
--- a/Tests/ManagedModelTests/CoreDataAssumptionsTests.swift
+++ b/Tests/ManagedModelTests/CoreDataAssumptionsTests.swift
@@ -67,4 +67,20 @@ final class CoreDataAssumptionsTests: XCTestCase {
     XCTAssertEqual(relationship.isOrdered, copiedRelationship.isOrdered)
     XCTAssertEqual(relationship.maxCount, copiedRelationship.maxCount)
   }
+  
+  
+  func testAttributeValueClassIsNotEmpty() throws {
+    do {
+      let attribute = NSAttributeDescription()
+      attribute.name = "Hello"
+      attribute.attributeType = .stringAttributeType
+      XCTAssertEqual(attribute.attributeValueClassName, "NSString")
+    }
+    do {
+      let attribute = NSAttributeDescription()
+      attribute.name = "Hello"
+      attribute.attributeType = .integer16AttributeType
+      XCTAssertEqual(attribute.attributeValueClassName, "NSNumber")
+    }
+  }
 }