I'm not sure if your dog is young or a puppy but it sounds like it. Puppies are especially prone to skeletal issues such as strains or breaks because their bones are still soft and growing. Same with the muscles, they are constantly growing and susceptible to injury. Just because she has moments of play that doesn't mean she's ok- dogs have an uncanny ability to override pain signals when something else is on their minds. Others have suggested patella issues, and while I can't speak to that I know Tanza is a breeder and knows well the issues that can affect our breed, let alone knowing about identifying issues. Good that you have an Appointment, in the meantime- continue to limit jumping and running so nothing furthers the problem. Is she has lax (loose) ligaments this can cause popping and will be a lifetime concern for injury if not carefully supervised. If it were me, I would want to contact an orthopedic, so if your vet doesn't have a definite cause that is a good route to go. Might be an initial cost but in the long run save you a lot
