World not Saving

Hello!

I have found a stronghold on my buddy's minecraft forger server which is quite far away from my house. Whenever I load that chunk though, it seems blocks just disappear or the portal loses enderpearls. I have no idea why this is happening. I suspect that for some reason the chunk the stronghold is in keeps resetting although I'm not sure why. Any help is appreciated because I don't know where to go for this.

Thanks for the help!