When trying 0.31.0-35, I was getting lamps that were invisible, when placing them touching on the lens-side of another horizontally-facing lamp that was running. (I didn't test to see if having it on or not made a difference, sorry.) Also, the lens-side of the first lamp turned invisible.

If you can't figure out what's wrong from just that, I can try to find out more specifics about what circumstances make it happen, later when I'm back at my main computer.

I do not fully understand what you are trying to say and i was not able to reproduce it yet. Do you use optifine or something like that?

No OptiFine. I will try to reproduce it, and try without all the other mods I've been using.

I could only reproduce it in one specific location of my test world and it was affecting both your flood light and the light from Greg's Lighting. I guess this might not be a bug in your mod after all. :)

Thank you btw. for the immense amount of constructive feedback, that really helps me in making the mod better. Both morally and technically.