Ideas
Dog walking has been glitchy for a very, very long time. Some worlds/neighborhoods are better than others. Windenburg is the worst.
Sometimes the problem is the walk becomes an endless loop until the player cancels it. Or has to resets their Sim.
Sometimes the Sim or the dog or both get stuck at one of the waypoints. Sometimes this is resolved by the Sim or the dog suddenly levitating to the other or to a further waypoint. Sometimes this "fixes" itself when they both reset and the action is canceled. Sometime the player has to reset their Sim. Which resets the dog. Then they can both go home and contemplate life in a Simulation.
Walking with a dog on any of the walking paths in SE, GrT or LS is just broken. The dog gets stuck at the first waypoint and the Sim goes on without them, but behaves as if they're still walking their dog. When they get to the end of the walk the dog either levitates to the Sim or they have to be unleashed or reset.
I say "sometimes" because "sometimes" - except for the walking paths - going for a walk with your dog works just fine. When it works as intended, it's one of my favorite activities. When we get new worlds, one of the first things I do in my test game is take a dog for a walk. It's can be a nice way to explore. Or not.
I'm a 100 years old and so is my dog, but we still enjoy our walks. I wish my Sims could also enjoy walking their dogs. 🙂🐶 Alas, this issue never gets much attention.