While the original foundation may have been not done well, this photo I took of this wall in England in the Lake District shows what sometimes happens to certain walls that have been built with throughstones in them, when the walls begin to settle.
The stones below start to separate and leave the 'throughs' straddling large see-through openings in the wall.
I wonder if this sort of thing ends up being less structural than having a wall with no throughs ?
A wall without throughs would allow the stones in a wall to nestle and mesh and lock into each other as it settles, rather than leaving the stones stranded balancing halfway up the wall (below the throughs they'd separated from) with nothing resting on them or holding them in place anymore.
Wallers have always been taught they should try to avoid laying one stone over three or more stones.
Why are throughstones any different ?