Minecraft: Is this a bug or a server problem?

I was playing around on my server and i saw this

https://imgur.com/a/ICfM7MN

Does anyone know what caused this? I've tried to relog on the server but its still there, tried to restart server still nope.
I used the plugin EpicWorldGenerator it seemed to work fine, but this chunk didn't seem to load and i can't find what would've caused it not loading.
My server specs are pretty fine 2GBs of RAM and an Intel processor.


Any help would be appreciated thanks,