Sewer odours inside can suggest a dry catch, split vent

https://academy.educause.edu/eportfolios/12410/home/reasons-why-homeowners-trust-plumbers

Drain odours inside can show a dry trap, broken vent, or partial clog; Geelong residential or commercial properties with big trees or older sewage system lines may require CCTV assessments to locate invasions and avoid repeating smells.