Bad really bad. I'll have to get one of mine out and give it a try. Maybe the meter dies with age and leads to that over exposure. Don't know if there is anything you could do about that.
Another possibility, though, is the shutter. A repair shop told me the old XA's are all getting relaxed shutter springs and lead to poor exposure accuracy. Would kind of make sense, since slower shutter speeds would lead to overexposure, of course.