Is there, perhaps a bit of oil rot at the head of the stock so that it's not bearing the full brunt of the recoil?
I've see that on tangs and at the rear of side plate actions, including one that I was just looking at yesterday. Bedding the stock's head may be required to move the point of impact between action and wood back to where it should be.
Just a guess on my part, but I would also look at the bolts and the holes in they wood that they pass through. Those holes can take a beating sometimes.