Cake Dissapears when pushed by piston

yes, my beautiful cake is gone! on my server, im trying to make a food court, so when someone pushes a button, a piston pushes out cake, but when the cake gets pushed by the piston, it dissapears without a drop! please help,

Steps to reproduce:

1. place down a cake
2. place a piston facing the cake
3. activate the piston
4. see the cake dissapear