In 2.5 hours (9:30AM ET), we'll be shutting the servers down for a few hours to perform various diagnostic tests for the lag issues. Unfortunately, the timeframe on how long these tests will take is fairly vague and downtime will be anywhere from 1-4 hours.
We'll keep everyone updated here & on the Discord server as things progress.
Edit
The servers are now back online. We've made a few changes based on our diagnostic tests to see if they resolve the lag issues. Just incase, we've also scheduled some additional diagnostics for tomorrow (but the downtime should only be 20-30 minutes when announced).
December 1 Edit
The Mystic Server has now been moved back to its own machine. The machine was moved to a new network center to see if that resolved the lag issues. If users continue to experience the lag issue, please let us know.