Once the caller of D3DKMTEnumAdapters2 has successfully received an enumeration of the adapters, it is the caller's responsibility to manage the lifespan of the adapter D3DKMT_HANDLEs. These handles are returned through pAdapters, and they must be closed with D3DKMTCloseAdapter.
Streamline calls D3DKMTEnumAdapters2 and doesn't close its output handles.
According to MSDN docs:
It's relatively benign. Still a bug nonetheless.