With spyder's help we've narrowed it down to our mid-frame z-buffer clear in Country Mode, which is perfectly valid to do, but a recent Oculus optimization or pipeline change doesn't like after a while somehow. Not having that mid-frame clear causes certain artifacts but does seem to avoid the problem.
The reason for the problem is definitely beneath our game, but knowing what triggers it may be help us accomplish the same need a different way. We had already suspected the z-buffer and tried changing how we clear it a month ago, and also updated to the latest versions of Unity and Oculus SDK, to no avail.
The reason for the problem is definitely beneath our game, but knowing what triggers it may be help us accomplish the same need a different way. We had already suspected the z-buffer and tried changing how we clear it a month ago, and also updated to the latest versions of Unity and Oculus SDK, to no avail.