That might be new to this post, but S**t stinks and no matter how many perfumes you dump in it, it is still S**t.
The deal is to have good vent that takes stink above the roof.
It is common that vent pipes extend few inches inside the tank and when the S.. level comes above the end, the only way stink can go is inside.
That's why smart owners check those things and do harpooning when necessary.
Years ago I could also buy Venturi-type roof vent ends, who would make vacuum in the tank, preventing the stink from entering the interior.