Intervals of spikes of Graphics.PresentAndSync show up in profiler

Hi everyone,

after playing a simple build on Android phone (LG G3) I have noticed that after approximately half a minute of smooth gameplay, game starts to slow down. I opened the profiler and saw that spikes of Graphics.PresentAndSync shows up out of nowhere and keeps showing up in certain intervals. It slows down gameplay drastically. I tried with simple scenes and even empty scenes without any object and without any elements on camera being turned on. I tried with all these things along an empty scene and without any luck:

-vsync off
-quality settings on fastest
-power saving mode turned off on phone
-setting targetFrameRate to 45 (just lowers down height of spikes a little bit, but with no luck - second screenshot)

And also problem is showing up when it is not development build and not connected to Profiler.

Does anyone knows what turns on Graphics.PresentAndSync and how to deal with it, so gameplay could run smooth as it is at start?