Faulty portable light source
Your light source has a habit of failing from time to time, flickering or even turning off for no perceivable reason or under certain specific conditions.
Alternate names: Faulty light sources, Faulty lamp
The first video game about Faulty portable light source was released on October 18, 2005.
This is for cases that are specific to light sources (which is surprisingly common) and thus not broad enough to warrant general malfunctioning tag.