Xsyon believes that certain actions are causing the lag, they are rebooting the server to add more diagnostics to identify which ones, and will hopefully be able to identify the offending actions. They can then work out a way to prevent this. Perhaps cooldowns on certain activities or something else.

Anyway, wanted to spread the word...

Edit - This is no way an official statement but due their workload I think we as a community can help them concetrate on fixing the problems and I know some people many not be in game as they furioously work their little butts off