Its sure thats from lag,u can check ur packetloss and bytes resend by pressing F5 button and if they keep going up then its from your lag.I will suggest you to do a relog when that happens because im sure this isn't a bug.
No. That's from the server, there's indeed a problem. Looks like this bug happens from time to time, but I have no idea right now how to reproduce it. Looks like some dialogs were appearing/responding, but some were not, it's pretty weird, I'll have to do some checks.
By the way, Patato, remove that amplifier thing. I'm not really allowing such things. It is illegal and players will believe that you have no lag, when you actually do. Don't use mods messing up with the server in that way. It is a kind of hack.