We have numerous halogen downlights in our rented home. They all have square discolouration in the gyproc around them very well demarcated. I think it is related to heat produced by the downlights affecting the gyproc and causing dust etc to attach to this area.

Our landlord is trying to suggest we have damaged the gyproc in some way. There are no other discoloured areas anywhere else on the ceilings.

Could heat from halogen downlights cause this problem?