Hopper bug

I created a mob farm few days ago and i put hopper to collect the mob drops. When i killed the mobs, its crashed. I reload, kill the mobs, crash again. After 2 time crash. Its work as usual. And this happen, there a skeleton at my farm. So i killed it. Btw the hopper is conected to a double chest. As soon as i killed it. It crash. But this time, i cant open my world. It's always crashing. I bet its because the hopper. Between the hopper itself or chest connected to hopper. I hope you fix this hopper bug as quickly as possible. Because i wanted to play with my sister.

When i try on creative. The hopper with chest work fine. Please tell me what happen and fix it.