It's not constant but it's noticeable; at quiet times I'll be thinking of some music and I'll get that repeating music excerpt thing for a while until it goes away when I'm distracted by something else. It's not so much intrusive as "that song again where did I hear that?"

It'll come back soon enough but funnily, it doesn't stick around after I've found out the full thing. One I remember most was the plants vs zombies 1 rooftop theme which I hadn't heard for 2-3 years. And yes it was a cathartic "Quest Complete!" when I found it again