I've found post dating back to 2015 of people complaining about the pet bug causing Poptops to be unable to sing their song, constantly stopping and restarting. Even placing their tether in such a way that they cannot move from the tether and at random times they still stop and restart. In about 15 minutes of listening to this poptop of mine it's only gotten about 20 seconds without restarting. I haven't managed to locate a mod that fixes it (still searching though) but ffs why hasn't this been fixed? It isn't like it should be rocket science eh?
I guess it is because they're still busy with some stuff. They are a company og few people, but a lot of work need to be done. I guess that's the reason of why it hasn't been fix yet.