Weird projector behaviour

Hi
never seen before: a Sanyo PLC-XF47, changes the pixels positions when a brighter light is present. A bit hard to explain but it seems like that the brighter is the light the wider is the image. We are using it with a 2.7 throw ratio lens, the screen size obviously increases as we throw some pure white light on the renderer… it is a 3lcd projector, any idea?
tx
S.