what u can try as server admin and player is :
LagGoggles
u can with this mod see which block have to high tickrate.
if is over 500+ or some more, look at this. when u say it it's fine it's be okay, if makes 10 poeple the same problem, it's be terrible and not good for your server.
make this in the bases and in your's.
Can't it be helped out, is your island for the graveyard