Flare or glare would not be in the same spot every time. It would depend on where in your picture is the bright light or area that flares.
A light leak would always be in the same spot but vary in intensity depending on how much light got in.
If the discoloration is contained within frames it means it is inside the film gate behind the lens.
If it seems unrelated to frames and is in the edges and spaces then it is coming from probably outside the film gate which would seem to indicate a bent back or bad seal or something to let light in.