If an object with Light Obstacle Behaviour has an edge that goes over the origin (0,0), then the light object does not show. The error message in the browser is :
If neither the X and Y positions of the Light Obstacle Behaviour object are 0, then the light object shows.
[edited] corrected the description as the edge has to go over the origin. A Light Obstacle can have an edge at 0 (X or Y) and have light objects work, as long as the edge doesn’t touch the origin.