diff --git a/src/gpgmm/d3d12/ResourceAllocatorD3D12.cpp b/src/gpgmm/d3d12/ResourceAllocatorD3D12.cpp
index 759b256c4..b83992eed 100644
--- a/src/gpgmm/d3d12/ResourceAllocatorD3D12.cpp
+++ b/src/gpgmm/d3d12/ResourceAllocatorD3D12.cpp
@@ -832,6 +832,13 @@ namespace gpgmm::d3d12 {
             ReturnIfFailed(GetHeapType(initialResourceState, &heapType));
         }
 
+        // Attribution of heaps may be abandoned but the original heap type is needed to
+        // check if sub-allocation within is allowed. Since default heaps do not require a
+        // persistent resource state once created, they are disallowed.
+        const bool isCreatedResourceStateRequired =
+            (heapType != D3D12_HEAP_TYPE_DEFAULT) &&
+            (GetInitialResourceState(heapType) == initialResourceState);
+
         // Abandon the attribution of heaps when isCacheCoherentUMA is true by always using the
         // custom equivelent of upload heap everywhere. This optimizes resource allocation by
         // allowing the same resource allocator to be used, improving heap reuse. However, CPU
@@ -947,8 +954,7 @@ namespace gpgmm::d3d12 {
         if (allocationDescriptor.Flags & ALLOCATION_FLAG_ALLOW_SUBALLOCATE_WITHIN_RESOURCE &&
             resourceInfo.Alignment > newResourceDesc.Width &&
             newResourceDesc.Dimension == D3D12_RESOURCE_DIMENSION_BUFFER &&
-            GetInitialResourceState(heapType) == initialResourceState && !isAlwaysCommitted &&
-            !neverSubAllocate) {
+            isCreatedResourceStateRequired && !isAlwaysCommitted && !neverSubAllocate) {
             allocator = mSmallBufferAllocatorOfType[static_cast<size_t>(resourceHeapType)].get();
 
             // GetResourceAllocationInfo() always rejects alignments smaller than 64KB. So if the
diff --git a/src/tests/end2end/D3D12ResourceAllocatorTests.cpp b/src/tests/end2end/D3D12ResourceAllocatorTests.cpp
index c51238e09..9d6b04a23 100644
--- a/src/tests/end2end/D3D12ResourceAllocatorTests.cpp
+++ b/src/tests/end2end/D3D12ResourceAllocatorTests.cpp
@@ -665,7 +665,7 @@ TEST_F(D3D12ResourceAllocatorTests, CreateBufferWithin) {
         ASSERT_SUCCEEDED(resourceAllocator->CreateResource(
             smallBufferDesc, CreateBasicBufferDesc(4u, 1), D3D12_RESOURCE_STATE_GENERIC_READ,
             nullptr, &smallBuffer));
-        ASSERT_NE(smallBuffer, nullptr);
+
         EXPECT_EQ(smallBuffer->GetMethod(), gpgmm::AllocationMethod::kSubAllocatedWithin);
         EXPECT_EQ(smallBuffer->GetSize(), 4u);
         EXPECT_EQ(smallBuffer->GetOffsetFromResource(), 0u);
@@ -683,7 +683,7 @@ TEST_F(D3D12ResourceAllocatorTests, CreateBufferWithin) {
         ASSERT_SUCCEEDED(resourceAllocator->CreateResource(
             smallBufferWithinDesc, CreateBasicBufferDesc(4u, 16), D3D12_RESOURCE_STATE_GENERIC_READ,
             nullptr, &smallBuffer));
-        ASSERT_NE(smallBuffer, nullptr);
+
         EXPECT_EQ(smallBuffer->GetMethod(), gpgmm::AllocationMethod::kSubAllocatedWithin);
         EXPECT_EQ(smallBuffer->GetSize(), 16u);
         EXPECT_EQ(smallBuffer->GetOffsetFromResource(), 0u);
@@ -701,7 +701,7 @@ TEST_F(D3D12ResourceAllocatorTests, CreateBufferWithin) {
         ASSERT_SUCCEEDED(resourceAllocator->CreateResource(
             smallBufferWithinDesc, CreateBasicBufferDesc(4u), D3D12_RESOURCE_STATE_GENERIC_READ,
             nullptr, &smallBuffer));
-        ASSERT_NE(smallBuffer, nullptr);
+
         EXPECT_EQ(smallBuffer->GetMethod(), gpgmm::AllocationMethod::kSubAllocatedWithin);
         EXPECT_EQ(smallBuffer->GetSize(), 256u);
         EXPECT_EQ(smallBuffer->GetOffsetFromResource(), 0u);
@@ -719,7 +719,7 @@ TEST_F(D3D12ResourceAllocatorTests, CreateBufferWithin) {
         ASSERT_SUCCEEDED(resourceAllocator->CreateResource(
             smallBufferWithinDesc, CreateBasicBufferDesc(4u), D3D12_RESOURCE_STATE_COPY_DEST,
             nullptr, &smallBuffer));
-        ASSERT_NE(smallBuffer, nullptr);
+
         EXPECT_EQ(smallBuffer->GetMethod(), gpgmm::AllocationMethod::kSubAllocatedWithin);
         EXPECT_EQ(smallBuffer->GetSize(), 4u);
         EXPECT_EQ(smallBuffer->GetOffsetFromResource(), 0u);
@@ -733,12 +733,65 @@ TEST_F(D3D12ResourceAllocatorTests, CreateBufferWithin) {
         ASSERT_SUCCEEDED(resourceAllocator->CreateResource(
             smallBufferWithinDesc, CreateBasicBufferDesc(3u), D3D12_RESOURCE_STATE_COPY_DEST,
             nullptr, &smallBuffer));
-        ASSERT_NE(smallBuffer, nullptr);
+
         EXPECT_EQ(smallBuffer->GetMethod(), gpgmm::AllocationMethod::kSubAllocatedWithin);
         EXPECT_EQ(smallBuffer->GetSize(), 4u);
         EXPECT_EQ(smallBuffer->GetOffsetFromResource(), 0u);
         EXPECT_EQ(smallBuffer->GetAlignment(), 4u);  // Re-align
     }
+
+    // Default heap using a required resource state of another compatible heap type is not allowed.
+    {
+        ALLOCATION_DESC invalidSmallBufferWithinDesc = baseAllocationDesc;
+        invalidSmallBufferWithinDesc.HeapType = D3D12_HEAP_TYPE_DEFAULT;
+
+        ComPtr<ResourceAllocation> smallBuffer;
+        ASSERT_SUCCEEDED(resourceAllocator->CreateResource(
+            invalidSmallBufferWithinDesc, CreateBasicBufferDesc(3u), D3D12_RESOURCE_STATE_COPY_DEST,
+            nullptr, &smallBuffer));
+        EXPECT_NE(smallBuffer->GetMethod(), gpgmm::AllocationMethod::kSubAllocatedWithin);
+    }
+
+    // Non-compatible heap type is not allowed reguardless of resource state specified.
+    {
+        ALLOCATION_DESC invalidSmallBufferWithinDesc = baseAllocationDesc;
+        invalidSmallBufferWithinDesc.HeapType = D3D12_HEAP_TYPE_DEFAULT;
+
+        ComPtr<ResourceAllocation> smallBuffer;
+        ASSERT_SUCCEEDED(resourceAllocator->CreateResource(
+            invalidSmallBufferWithinDesc, CreateBasicBufferDesc(3u), D3D12_RESOURCE_STATE_COMMON,
+            nullptr, &smallBuffer));
+        EXPECT_NE(smallBuffer->GetMethod(), gpgmm::AllocationMethod::kSubAllocatedWithin);
+    }
+
+    // Custom heaps should use a heap type inferred by the resource state required.
+    {
+        ALLOCATION_DESC smallBufferWithinDesc = baseAllocationDesc;
+        smallBufferWithinDesc.HeapType = D3D12_HEAP_TYPE_CUSTOM;
+
+        ComPtr<ResourceAllocation> smallBuffer;
+        ASSERT_SUCCEEDED(resourceAllocator->CreateResource(
+            smallBufferWithinDesc, CreateBasicBufferDesc(3u), D3D12_RESOURCE_STATE_COPY_DEST,
+            nullptr, &smallBuffer));
+        EXPECT_EQ(smallBuffer->GetMethod(), gpgmm::AllocationMethod::kSubAllocatedWithin);
+    }
+
+    // Unspecified heap type should use the heap type inferred by the resource state
+    // required.
+    {
+        ComPtr<ResourceAllocation> smallBuffer;
+        ASSERT_SUCCEEDED(resourceAllocator->CreateResource(
+            baseAllocationDesc, CreateBasicBufferDesc(3u), D3D12_RESOURCE_STATE_COPY_DEST, nullptr,
+            &smallBuffer));
+        EXPECT_EQ(smallBuffer->GetMethod(), gpgmm::AllocationMethod::kSubAllocatedWithin);
+    }
+    {
+        ComPtr<ResourceAllocation> smallBuffer;
+        ASSERT_SUCCEEDED(
+            resourceAllocator->CreateResource(baseAllocationDesc, CreateBasicBufferDesc(3u),
+                                              D3D12_RESOURCE_STATE_COMMON, nullptr, &smallBuffer));
+        EXPECT_NE(smallBuffer->GetMethod(), gpgmm::AllocationMethod::kSubAllocatedWithin);
+    }
 }
 
 TEST_F(D3D12ResourceAllocatorTests, CreateBufferWithinMany) {