This causes a lot of long, random "Hold On' dialogs taking anywhere from 30 seconds to several minutes.

Main thread callstack:

ntdll.dll!NtWaitForSingleObject()
KERNELBASE.dll!WaitForSingleObjectEx()
Unity.exe!WinApi::Baselib_SystemSemaphore_Acquire(UnityClassic::Baselib_SystemSemaphore_Handle)
Unity.exe!UnityClassic::Baselib_SystemSemaphore_Acquire(UnityClassic::Baselib_SystemSemaphore_Handle semaphore)
Unity.exe!Baselib_Semaphore_Acquire(Baselib_Semaphore * semaphore)
Unity.exe!Semaphore::WaitForSignal(int)
Unity.exe!GfxDeviceWorker::WaitForEvent(GfxDeviceWorker::EventType type)
Unity.exe!GfxDeviceClient::WaitForPendingPresent()
Unity.exe!GfxDeviceClient::BeginRendering(ClientDeviceWindow * handle)
Unity.exe!ThreadedWindow::BeginRendering()
Unity.exe!GUIView::DoPaint()
Unity.exe!GUIView::RepaintAll(bool performAutorepaint)
Unity.exe!Application::TickTimer()
Unity.exe!MainMessageLoop()
Unity.exe!WinMain(HINSTANCE__ * hInst, HINSTANCE__ * hPrev, char * szCmdLine, int nCmdShow)
Unity.exe!invoke_main()
Unity.exe!__scrt_common_main_seh()
kernel32.dll!BaseThreadInitThunk()
ntdll.dll!RtlUserThreadStart()

Gfx thread callstack:

ntdll.dll!NtDelayExecution()
KERNELBASE.dll!SleepEx()
d3d11.dll!00007FF93D47E84B
d3d11.dll!00007FF93D47E918
Unity.exe!GfxDeviceD3D11Base::GpuRecorderGetFrequencyInternal(unsigned int slot, unsigned __int64 & freqValue)
Unity.exe!GpuRecorderManager::FrameTick(GfxDevice & realDevice)
Unity.exe!GfxDeviceWorker::RunCommand(ThreadedStreamBuffer & stream)
[Inline Frame] Unity.exe!ProcessGfxCommands(GfxDeviceWorker &)
Unity.exe!GfxDeviceWorker::RunExt(ThreadedStreamBuffer & stream)
[Inline Frame] Unity.exe!GfxDeviceWorker::Run()
Unity.exe!GfxDeviceWorker::RunGfxDeviceWorker(void * data)
Unity.exe!Thread::RunThreadWrapper(void * ptr)
kernel32.dll!BaseThreadInitThunk()
ntdll.dll!RtlUserThreadStart()

Note: not reproducible on 2021.2, 2022.1 or 2022.2.