Same settings, different render results

[joethelion]

I`m puzzled here. Using Vray for Sketchup. I don`t change any setting at all, don`t even click in the scene or the settings menu, I just hit `R` once again, and the two renders have slightly (but noticeably) different lighting. Especially great problem with animations. Tried with and without physical camera.
Thanks in advance.

[joethelion]

Solved: The rectangular light at the top of the room was in the same plane with the ceiling, hence the unpredictable and variable lighting. Once I moved the light 0.1 cm down, it was OK.