[GearVR] Performance loss after rebuilding and relaunching game several times

I have a problem with performance loss on rebuilding and relaunching project several times in a row. Looks like some sort of cache getting full or smth. UE4’s ‘Profiler’ tool shows Stat Thread to jump sky high hence a lot of CPU stalls. Is anyone familiar with stuff like this?
Right now to fix this I try deleting and building project → reboot phone → ‘Optimization’ function with RAM cleaning. It usually helps but result is not 100%. I wonder is there some sort of Task Manager app that can clean all the RAM and cache files time to time?

UPD: 4.16 has same problem. The easiest way to see it is: use GearVR throttling node with CPU and GPU modifiers set to 0, ‘stat raw’ command shows handy realtime threads, jitter can be spotted there as well.

Looks like this issue is fixed in 4.18. With 10+ play tests I couldn’t get ‘dirty build’, results were good and constant.