Random block updates in multiplayer servers

I'm trying to make an automatic pumpkin farm on a multiplayer server. It requires a block update from when the pumpkin grows.

I expected the pistons to move when the pumpkin grows.

What actually happens is that the pistons are triggered without a block update. I inspected everything, and it seemed normal. I tried it on a singleplayer world, and the farm did its thing correctly. I don't know if it's the server or the lag I'm having. Please fix this bug in the next patch.

Here's the tutorial of the pumpkin farm I made.
https://www.youtube.com/watch?v=6NQRB0UM9gM