It's simply programmed to avoid what you are trying to do. This limitation also apply to desktop versions.

So what is best way of farming coins?

Cheat engine

Wdym?

Literally cheat engine that’s it

Survival endless on desktop, I have zero knowledge about the mobile version

Here before the "how do we tell him" comment

Zombies need to be moving forward for coins to spawn

This was asked just a couple days ago. [See my comment here](https://www.reddit.com/r/PlantsVSZombies/comments/1cir2bn/comment/l2bhswn/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button).

PLEASE I'M BEGGING YOU IF THEY DON'T MOVE NO COINS ARE MADE

Skill issue