After joining a party to help a fellow Epocher out in a mono, and then leaving said party, whenever a previous party member enters an echo, it says “loading echo” and then you get the “quest thingys” as “slay enemies to locate said gate etc”. Bar fills up as previous party member clears his way through, however you’re not in the echo and trying to enter an echo for yourself shows an error “Already in Echo-LP56” etc.
Doublechecked I had left party.
Completely exiting and relaunching the game fixes it thankfully.