light not correct

I want to create this feeling of led strips. When using just luminant textures, the whole file gets overflown with weird spots and sparkles, so this is not an option. So I need to use line or rectangle lights. The problem with lines is sometimes its either too thick or it shines to all sides, so I really need thin long rectangles.

And then I get this problem, I have this more often and is really annoying. Any clue how to fix this or is this just a bug?

To clarify the image: the light source (rectangle) is 3 meters long and about 17 cm away from the wall, but the result is just super small, like it is only 50 cm long.

@DeKoetsier , thanks a lot for the report - We are aware of this. To ensure that it’s really the same behaviour though can please try to increase the thickness of the glass itself (or basically of any element the light is shining on), as that should also make the light area larger. Thank you in advance, I will bring this topic up again once more as well.