On Unreal Engine 4.8.3, using the Shift+O key combination an odd number of times (once, three times, etc) will result in the editor (but not the level viewport) slowing to a crawl and eventually crashing if an intensive operation is performed. Different operations seem to have slightly different effects when crashing, as resizing the window will typically not result in the Unreal Crash Reporter being displayed, but saving a material will.
Reinstalling both the Epic Games launcher and Unreal Engine does nothing to solve the problem. The problem also seems to occur in multiple projects. Clearing the Shift+O keyboard shortcut (originally bound to Level Editor > Surface Selection OR) using the Editor Preferences also does not solve the problem.
Further testing has revealed that this also occurs on the 4.9.0 preview 4, and is not necessarily dependent on how many times the hotkey is used.