This is on a 1984 Nishiki International. (Downtube friction shifters.) I haven't changed any part of the drivetrain, and I would be surprised if the previous owner did.
The limiter bolts are not the cause. I don't think it's the wire tension either. The problem was present both before and after having my derailer hanger straightened.
Could the spring in the RD have weakened over the years?