This just happened to me and a friend like 5 minutes ago and we've talked to others in-game who have verified it. I'm not sure if this is the right forum for this, but all of a sudden when we switched worlds, the Halloween decorations were all gone and the seasonal events in Ul'dah are no longer available. I was super stoked about the seasonal addition to things, so bringing this up ASAP in hopes that it'll addressed. Thanks for the hard work, guys! Still lovin' the hell outta the game!