Bears can smash fences, so it's likely the bear did so, in which case it's working as intended. Bears are the only animals that can smash fences (Njerps can probably deconstruct them, but as they can simply climb fences they don't bother deconstructing them), but the other predators can bypass them either by running through them (lynx and smaller) or (I assume) jump over (wolf). I suspect wolves only jump fences to get at prey, and that both bears and wolves pass though (trapped) openings in the fence rather than go through the extra effort of dealing with the fence itself.