What Lunarbrick said.
I've not encountered this void lag.... gap whatever thing .... I assume its because no chunks are being loaded? or sent.. which does have a lot to do with your connection to the server. And bukkit itself still not being very optimized as its current issue is general degrading in performance after a few hours. Which does lower tps of server and result in chunk sending delays.....
However most the time its a client side/your internet connection issue.