Yeah, I tried it several times and had the camera in the exact same position - the lighting didn't change.
How do you know? Do you use tungsten lighting, halogen, fluorescent, other discharge lamps, led? Some of them (fluorescent mainly) cycle between different colors, and since you shot at 1/40 instead of 1/30 or 1/60 (or 1/25 and 1/50 in parts of europe and japan), you only got part of a cycle, and some of them exhibit very uneven spectrums (all discharge lamps to some extent, including fluorescents, and LED lights to a large extent) and can cause certain colors to show up more or less depending on what it is. There's also the off chance of UV or infra-red based problems, especially with the LED laps (most "white" LEDs are actually UV leds that have phosphors), which may affect one more than the other