diff --git a/media/gpu/windows/d3d12_copy_command_list_wrapper.cc b/media/gpu/windows/d3d12_copy_command_list_wrapper.cc
--- a/media/gpu/windows/d3d12_copy_command_list_wrapper.cc
+++ b/media/gpu/windows/d3d12_copy_command_list_wrapper.cc
@@ -60,7 +60,16 @@ D3D12CopyCommandQueueWrapper::D3D12CopyCommandQueueWrapper(
       command_list_(std::move(command_list)),
       fence_(base::MakeRefCounted<D3D12Fence>(fence)) {}

-D3D12CopyCommandQueueWrapper::~D3D12CopyCommandQueueWrapper() = default;
+D3D12CopyCommandQueueWrapper::~D3D12CopyCommandQueueWrapper() {
+  // Drain the COPY queue before releasing the command queue / allocator /
+  // command list. Callers (D3D12VideoEncodeAccelerator) hold raw
+  // ID3D12Resource pointers in in-flight CopyTextureRegion commands; D3D12
+  // command lists do NOT AddRef recorded resources, so releasing those
+  // resources (or this allocator) while the GPU is still executing the copy
+  // is undefined behaviour. SignalAndWaitCPU enqueues a fence signal after
+  // the last submitted work and CPU-blocks until the GPU reaches it.
+  fence_->SignalAndWaitCPU(*command_queue_.Get());
+}

 bool D3D12CopyCommandQueueWrapper::CopyTextureRegion(
     const D3D12_TEXTURE_COPY_LOCATION& dst_location,
diff --git a/media/gpu/windows/d3d12_video_encode_accelerator.cc b/media/gpu/windows/d3d12_video_encode_accelerator.cc
--- a/media/gpu/windows/d3d12_video_encode_accelerator.cc
+++ b/media/gpu/windows/d3d12_video_encode_accelerator.cc
@@ -984,6 +984,12 @@ bool D3D12VideoEncodeAccelerator::DoEncodeTask(
 void D3D12VideoEncodeAccelerator::DestroyTask() {
   DVLOGF(2);
   DCHECK_CALLED_ON_VALID_SEQUENCE(encoder_sequence_checker_);
+  // input_texture_ / upload_buffer_ may still be referenced by in-flight
+  // COPY-queue work submitted from CreateResourceForSharedMemoryVideoFrame()
+  // when the delegate early-returned before the encode-queue CPU sync. They
+  // are declared after copy_command_queue_ and would otherwise be released
+  // first; explicitly drain the COPY queue before member destruction.
+  copy_command_queue_.reset();
   delete this;
 }