At first I was thinking that my memory was just failing me, but then I started to pay more attention to it. One of my toons finds herself in Arcstone after patch day, but that wasn't where I left her.
Was that was the last instance mission you did? When EQ isn't sure where to put you when a zone shuts down thats where you end up. A lot of later expansions dump you at the safe spot in PoK at the PoT stone. Been a while but I used to end up in LDON camps frequently.
Sometimes what will happen is that you are placed at the place where you last zoned into or out of an instance, no idea why. Can happen if you log out in an instance or if you log out in open world but have seen this multiple times after a server patch.
Where were you attempting to log into? If you are attempting to login to a housing zone that has not previously booted up, such as a guild hall, it's going to kick you to one of those various safe points that you last exited and that isn't a bug.