Weird and very specific bug in 4.11/4.12

I have a VERY strange bug occuring in 4.11 and 4.12, but only with very specific circumstances. Unfortunately I need those things to work under those exact circumstances.

Specifics:

  • Using lighting channels (channel 0 for most light, and channel 1 or 2 for directional light on movable characters)
  • Playing on an Oculus Rift Dk2
  • A couple of meshes are quite large (not many polygons, but they cover large areas, perhaps 10x50x8 m each or so)

What happens is that very rarely, one eye gets a very bright image, which I think looks like shadowcasting suddenly turned off. It’s just for a frame or to most of the time, and if I’m lucky I can find the exact direction to look so I can get it to bug out for a longer amount of time. So the bug is apparently affected by the view direction and/or location. It’s quite annoying as I would really like to be able to use these features together. =)