Yes, setting GPU-Z.exe to run on a dedicated video card resolves the problem. But that behavior is strange, because without this setting GPU-Z anyway use dedicated video card periodically while running.
I have one more problem on other laptop (Dell 5537)
GPU-Z does not show full info about my graphics card, including DC5.0 support. Setting "switchable graphics" to Radeon for GPU-Z.exe does not change nothing. Full info displayed for a moment, and then disappears