VSync (GTX.WaitForPresent) getting 50 ms in Editor

Hi everyone. I ran into a problem.

Now we develop mobile game. All was fine, but now i'm start getting some strange behavior of VSync (GTX.WaitForPresent).

When i start scene in Unity Editor, i have only 20 fps on the top pc, in mobile game) Yep, i thought, that was something wrong with my code or may be graphic, etc.

But. In profiler Behavior Update getting only 0.52 ms. GTX.WaitForPresent - 50-60 ms. What it can be?

And, the most important is that in build on android all works fine! Even with VSync. No performance problems at all.

Unity version - 2017.0.1f. Still occurs sometimes in Unity 2017.2.f03.