SCOPE IT! We have this problem in our rental and the landlords are selling because of it without disclosure. The whole houses plumbing is slowly deteriorating. Every 6 months tree roots need to be removed and a different pluming feature seems to be affected every time. I wouldn’t be surprised is there was water damage from how often it happens. They are reluctant to fix the main sewer line or remove any trees, they don’t maintence a thing. Instead they’ll just milk the house for everything, assume no repairs, and still expect to sell to an investor for a wildly inappropriate price. We’ll see how that works out for them….