The obsidian breaker plug-in was causing game-breaking issues and has been temporarily removed. Fixing this is a high priority, and will be dealt with as soon as we're able. While unfortunate, it's better we find a permanent fix for this rather than have the server crash every 12 seconds.
I've reenabled the plugin with a possible fix, but if it causes another crash, it will be removed again. There are very few available Obsidian Breaker plugins, and the one that we're having issues with is the only one that actually works.