IddCxSwapChainSetDevice returns DXGI_ERROR_ACCESS_LOST

When I run the IndirectDisplay driver sample (https://github.com/microsoft/Windows-driver-samples/tree/master/video/IndirectDisplay) IddCxSwapChainSetDevice returns 0x887a0026. Visual Studio describes this as "The keyed mutex was abandoned." and looking online indicates that this is the DXGI_ERROR_ACCESS_LOST code. I can't find any information on what would cause this.

What would cause this "The keyed mutex was abandoned" error in an IddCx driver?