Smells coming back up, especially when related to the outside, could be indicative of a larger sewer issue. That’s why they were so happy to respond to our issue.
In our case, there’s a flap that is supposed to only allow stuff out. Sometimes that flap gets stuck open and can’t shut. If the sewer levels rise above that flap, now stuff is flowing the wrong way back into the private side of the sewage line.
Before you call the plumber, try calling the city. We had sewage backing up into our showers so we called the city and they found the issue was on our side but still fixed it for us for free.
Worst case scenario, they say it’s not their problem. Best case scenario, they give you the solution or even fix it themselves.