This is actually a known bug that we could not fully fix. If you spam click in the game, you can break the cat's movement.
But I do have some insight as to why going around walls may have been a little dicey. Our path finding algorithm is only supposed to consider squares within a specific range. When you click the other side of a wall, that range is actually massively increasing, depending on how many squares you have to move to get around that wall. If that range happens to be broken, the cat will go to the spot that sits closest to your destination "As the Ghost Flies".
In retrospect, I think what we could have done is limit this to simply spots at the edge of that range. Also, if we implemented "Hunting Stance" as mentioned in reply to said previous commenter, you'd get the feedback you need to know that the cat would get to your chosen square. In other words, you had the opposite problem he did. While he went 1 square at a time at first, you pushed how far you could click away from the cat, and arrived at the same issue.