I don't know about that, i'm in the US on an NA server and i was getting massive lag spikes for no apparent reason. Two days ago, i couldn't go 3-4 steps in game without disconnecting. i checked my ping and everything, not that i saved it, stupid me, but the last few days have been very laggy. a bunch of us were in Limsa and all of a sudden Red Pokeballs of disconnect everywhere for all but like 3-4 people.

I could guess some of your issues may be related to Optus, but...i honestly am not sure if that's fully the reason. many people in the South East part of the US have been having this problem.