Piston resulsts drops of FPS

I have a sugar cane machine, and when I hit the button to push sugar cane, I have a drop of FPS (I have 60fps and it's dropping at about 25fps), and even when there are not sugar cane to push, the lag still here. I have 42 pistons activated in the same time, but I never had that before.

Specs : I am on server (OMGSERV), I am on Spigot, I don't use Optifine, and I have the very last version of Java (8, update 231, for client, not on the serv, serv is on Java 8).