You recently closed my issue SPIGOT-1760 because I didn't reply in time, but this is being a pretty major bug still.

It happens frequently that a chunk won't load until you use F3 + A which I think isn't normal.

Also, when players are exploring in the normal world, the server will start lagging a lot while just walking normally thru chunks. We tested this before I created this issue and as soon as we stopped exploring there was no lagg at all, when we started exploring again the lagg came back.

Not sure if you need any other information.