The 2-3 hour bout of game-breaking lag on Orien this weekend (and 2 weekends ago) was something altogether different from the normal lag we're used to. It wasn't the suttering, freezing, rubberbanding and action queueing backlog that we usually see when there's high load on the servers.
Instead, it seemed to be almost entirely related to things that would read/write from the database (i.e. banking, buying/selling from vendors, logging in/out, etc.)
For example, I went to my airship, hit the banker, gave up waiting on the bank windows to appear after literally more than a minute, teleported to the Feywild castle and stepped into Wake Me Up Inside and was 2+ minutes into the quest and fighting mobs when the bank windows suddenly popped up.
I quickly closed them as I was mid-combat and 15-30s later, they appeared again. That open/close cycle on the bank windows continued for the next few minutes before finally stopping.
Note that during that entire time, I was running the quest normally and with no other symptoms of lag. Zoning from my airship to the Fey castle and then into the quest was normal. Combat was working smoothly, movement was normal, etc. I was in the quest solo on R4 with no hires, pets, etc.