In the server logs I see the following happening:
Code:
[21:39:46] [Netty IO #3/WARN]: Selector.select() returned prematurely 512 times in a row; rebuilding selector.
[21:39:46] [Netty IO #3/INFO]: Migrated 2 channel(s) to the new Selector.
And then everybody disconnects. It seems that a workaround for a bug in netty or java (not sure which yet) activates to prevent a crash. That is good, however the result is that the connections are dropped and everybody has to reconnect. Which isn't good obviously.
md-5, the guy behind Spigot, sais there is nothing he can do about it: https://github.com/SpigotMC/BungeeCord/issues/455
On netty's Github people are discussing various Linux kernels but I'm not sure if that is going to be any help to us since we're already on a newer kernel then the ones they are talking about: https://github.com/netty/netty/issues/2616
When we know more we'll post an update.