Sprites aren't separated individually. It's one big picture that gets overrided. You probably have a mod enabled that replaces the objects.png file. You could try putting this mod on top of all your other mods in the game using the arrows on the right.

Nope. I've checked every single mod and this is the only pipe mod that I've subscribed.

You probably have another mod that is overriding it. Check to see

This mod isn't working for me when I applied it. No changes ar all.

Thanks a lot :)

You should join Prison Architect modding community: https://discord.gg/8Yw7uDdnTM

Great mod buddy