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I also have this problem, specifically when playing Wiz using Firebird Archon. Even with the Vyr Archon, with the intense attack speed, I don't get disconnected but with FB I cannot make it through a puny GR70 without being disconnected. Almost always happens when using Arcane Torrent - Static Discharge. I even tried switching to the Flame Ward rune thinking that might be the problem, but it helped not at all.