Melon Glitching on a server

What I expected to happen was...:
I will get melons after i break the melon block

What actually happened was...:
Melon disappear and seed act as growned and did not stick to air block.but no melon was appear and no melon was dropped.and it dont let me step on the place where the melon is on.

Steps to Reproduce:
1. Grow a melon seed
2. break the melon with a axe with Eff 4
3. melon disappeared and no melon was droped

Things that happen:
When i use hands.I break the dirt underneath it.
When i use rail on it.It eat the rail and appear again.
This dont work when break with hands.

Server: mc.thenova.net The Nova by ExplodingTNT