to me it seems like it is the CRC or one group needs to be tightened. Inside these older Nikkor W.A there are scribe marks showing the alignment of the element or group retaining rings, which is basically how much to tighten or torque the retaining ring down. I can assure you it is possible to improve or degrade the performance of the lens by missing or hitting that original scribe mark.
It could be the CRC mechanism, but I'd check for haze first before taking it apart. You'd be surprised how many lenses of "a certain age" have it, and how a seemingly tiny bit can degrade performance.