Any of you tried any Japan server? i have same problems like you on EU server but no lag at all on Titan (Japan serveR).
So is definitely a problem with EU/NA data center, there is something (router/server/switch/something) which drop packets for us... arround 5% loss during 30 mins of monitoring.

I've send a mtr log to support, i hope someone see it and identify those IPs which lose packets.