Water being pushed by a piston causes grey particales

After pushing a waterlogged piston it spawns grey concrete particles

I tried to design a sugarcane farm and got distracted after particles spawning
https://drive.google.com/file/d/17Fd43mPujcyVZsYv8QTgwLLlVTIh1fLZ/view?usp=sharing
it could also be .name