Lights acting weird


Sometimes the light cant decide which is the front and which is the back.
These lights havent been changed yet yesterday the green light was lighting the front of the amps to the right like the blue lights at the left. But today the green lights arent lighting the front of the amps but are lighting the back of the amps instead.

I have seen this happen in several places, most noticable when I use a light to illuminate a picture on the wall, I set it so it can be seen from one side but not the other side of the wall. The next time I log in the light is lighting the wrong side of the wall and the picture is in darkness, something changes without me doing anything.