Update: After loading the game, I found two Oculus corpses levitating above a chasm and no longer falling into it. But I can't remember if I saw them each time I reloaded the same save.

Author of the bug-report will be away from his computer for a few weeks. He asked me to answer for him.

He has desktop computer with integrated graphics on i5 4460. Also assigning high perfomance processor to CoherentUI_Host.exe helped him to raise FPS to ~40 in battle and ~50 when nothing happens. But when FPS jumps he still experiences short freezes.

Also he says that he has comparable perfomance on much slower notebook.