This is a failure on multiple levels. When a laundry is relocated to a second floor and venting is run through the attic serious damage can occur if basic design and systems aren’t put together well. Blockage at the roof vent or a disconnect in the attic can lead to mildew problems or worse. Multiple issues have led to consequences that will be costly to cleanup and either violated building code or lacked best practices, judgement and the right materials.
Sometimes I just shake my head and feel sorry for our customers.