No. The issue is that an assumption they make in the unsafe block does not actually always hold true. They changed the safe rust code to strenghten the (incorrect) assumption they made in the first place, because that is way easier than rearchitecting the unsafe part. I.e. if the unsafe part was somehow to be written safely, the mitigation they introduced now would not result in any difference in behaviour, it would be correct behaviour both before and after.

Tldr: the problem lies in the unsafe part

I'll admit, I haven't looked at the code. I would stand by my comment of the unsafe block being a start point.

Countering that however, what is the difference to just debugging effectively? Not sure. I suppose it's down to the people that identified it and fixed it at the end of the day to say if there was any benefit.