Big Dig Bugging?

[Blueboa96]

I started a new server for Big Dig, there is only two of us on it but it is bugging real bad. I was trying to figure out what the reason for it was. Everytime we get rid of a block it appears back in a rainbow color and when you go into the rifts, it starts bugging real bad turning blocks blue and sputtering it. I have no resource packs on, and I am running minecraft with 11gbs of ram.