The crack in the wrist was a major issue with the SVT in service. Eventually much thicker stocks became standard which seems to have solved the problem. Early thin stocks reused in refurbishment commonly have bolts (as shown) put through the wrist. I have a former sniper rifle that has two bolts. These seem to solve the problem and I've shot this one a lot with no issues. I've noticed that similar fasteners are available in the hardware and it wouldn't be difficult to make a "correct" repair. That's what I'd do if I had one I liked and wanted to shoot (and that wasn't highly original and valuable). Gluing probably won't solve the issue. The problem is not related to specifics of bedding in a particular rifle. There is no tang in these guns- a large flat at the rear of the receiver is driven back onto a mating area in the stock. The small cross pin that holds the front of the receiver in the stock doesn't appear to be functional in taking up recoil.
Ridolpho