Not Mormon, and with nowhere near the level of harassment, but still.
My parents had to fight to get married, as my mum was raised Catholic and my dad Protestant and even in the 70's in the Netherlands that was an issue. They wanted to marry in a church and had to work hard to get a priest and pastor willing to cooperate, but that came with the promise that any children would be inducted in both faiths.
By the time I was old enough to care they'd both lapsed and the only reason I did some Catholic things was because I was enrolled in a Catholic school as a child (pre-highschool).
When I was an adult I moved cities and when I arrived in the new city I suddenly got all sorts of pamphlets from both the local Catholic church and Protestant one. It turns out they checked when people moved with citizen registration. I decided I did not want that, so inquired as to how to stop it.
The protestant one was easy, I just had to write in I was no longer religious and they stopped. But the Catholic church happily informed me that since I was baptized I could not stop being a member of the church, that would need an excommunication. They stopped bothering me though.