That's probably because when using Spigot it's the server that freezes, not the client.
EDIT:
If we'd want to fix it we'll probably have to split the data up into multiple packets. I have no idea if that's going to be hard to do.
EDIT:
If we'd want to fix it we'll probably have to split the data up into multiple packets. I have no idea if that's going to be hard to do.