Lysandus died in 3E 403 and this is confirmed in The Third Era Timeline so it has not been retconned.But in the intro Uriel VII also says that"Its subject is King Lysandus of Daggerfall, a man who died over a year ago, honorably, on the field of battle."
The letter was send during the War of Betony .Serveral years ago should be more than two years espcially since the game starts on the 4th of Morning Star so the emperor was probably talking with the player in late 3E 404 but maybe that is still what it means.Several years ago, I sent a letter to Lysandus' Queen Mynisera.
What really confuses me is this line from The Warp in the West:
thought at first that it was suspiciously similar to what happened to another agent of ours in High Rock but a short time before, where a freak storm had shipwrecked him in the Iliac Bay near Privateer's Hold.
It seems rather strange to call 12 years a short time before,this seems to imply that the agent didn't arive in 405 but only a short time before the events of the warp. It could of course mean that the timeline was messed up by the dragon break but people in the warp only seem to have missed a single day. So has this been retconned or is there some other explanation?