»Pistons don't work

I can't break pumpkins and melon with piston , please fix it

 

You need to use this format for reporting a bug/glitch

Type of bug:
Tell us what type of bug you're reporting. Examples are: Lag, No permission, Lost items, Error, Cannot connect etc etc.

Server:
Name the server, examples are: Factions. Survival etc etc.

Arena:
If possible name the arena, examples are: SG-Arena12, Anni-02 etc etc.

Date and Time:
It will greatly help us out if you could provide us with the date and time.

Visual information:
If would be great if you could provide us with screenshots or video's. This will help us re-create the bug.

 

That's not a bug, It's intended to prevent players from building big auto farms and afking.