Bad waterless trap?

[wkcox]

I have new 2017 Leprechaun, and it has a sewer smell in the BR from day 1. Thetford 42072 toilet taken apart and checked and looks ok. Tanks are clean now, and of course, the smell is gone. Has anyone had one of these waterless traps go bad?

[wkcox]

[Dwilcox]

Yes they can. Or hair or a tooth brush can hold them open. Smell the sink and if it stinks, well there you are. Even a water seal trap can loose it's prime on the road.