UI freeze (Intel Nuc6i7kyk + UWP)

[Gnitry]

I have:
Intel NUC6i7kyk (all drivers updated), graphics card: Intel Iris Pro Graphics 580
Windows 10 Pro (latest updates)
Monitor 4K Sharp PN-K322BH with touchscreen (also tried another monitors)
Fullscreen UWP application (target 10.0; Build 14393)

I draw one 3d model drawn by SharpDx. Very often, when I click Windows button to show start menu and click again to hide it, application becomes unresponsible - for a few seconds it doesn't receive touch, mouse and keyboard events. When this happens sometimes UI continue drawing, sometimes whole UI stops drawing (video: https://drive.google.com/file/d/0B1LIS8G55R7-cjR3aWpUWW1hY2s/view?usp=sharing)
When I profile application while it freezes, i found that the main thread freezes at this line
"SwapChain.Present(0, DXGI.PresentFlags.None);" . It becomes normal when I minimize/maximize application.
This bug repeats on two similar PC, but not on my notebook.

Also I found that when Start menu shows/hides there are little video lags in directx drawing.
It is shown in this video (Helix Toolkit sample): https://drive.google.com/file/d/0B1LIS8G55R7-NkVfalFnNVcyVUE/view?usp=sharing

The same application works find without lags on my notebook (GeForce GTX 1060): https://drive.google.com/file/d/0B1LIS8G55R7-elc3Qnlya3RhcUk/view?usp=sharing

I think, that these two problems have common roots. What do you think could it be?
Right now I can't publish sources, but can process any research actions.