In this picture, you can see the light shining as it should.

But if I move back even a little, it disappears:

But if I take off in height, it stays visible! It's visible even from the top of this cavern:

It does this with shaders off all the way to max. Any way to change/fix this, or does anyone have any idea why this happens? There are no invisible bricks blocking the line of sight either.
tyia, achoo