Just so that people are clear, this issue has absolutely nothing to do with the emergency maintenance that was done earlier today. It was mearly a coincidence that the servers came back up close to the time that ISPs flick the switch on throttling (7pm normally) Nor is this SE's servers cracking under the strain of all the Early Access players. This is our internet provider throttling a very specific type of internet traffic and registering this game as said traffic.

It presents as lag but if you were to run a speed test both your download, upload and ping would all appear to be normal.

People may not have experienced this in previous beta's because the P2P traffic would have been a lot less due to fewer people being around. But once Phase 4 and Early Access hit and player numbers sky-rocketed the P2P traffic increased and limits placed on it have a much bigger effect.

I hope both SE and BT can work together and resolve this quickly or else none of us will really be able to play in peak times.